Computers And Internet

Computer Security

2008-04-04T10:55:00.000+07:00

is a branch of technology known as information security as applied to computers. The objective of computer security varies and can include protection of information from theft or corruption, or the preservation of availability, as defined in the security policy.

Computer security imposes requirements on computers that are different from most system requirements because they often take the form of constraints on what computers are not supposed to do. This makes computer security particularly challenging because we find it hard enough just to make computer programs just do everything they are designed to do correctly. Furthermore, negative requirements are deceptively complicated to satisfy and require exhaustive testing to verify, which is impractical for most computer programs. Computer security provides a technical strategy to convert negative requirements to positive enforceable rules. For this reason, computer security is often more technical and mathematical than some computer science fields.[citation needed]

Typical approaches to computer security (in approximate order of strength) can include the following:

* Physically limit access to computers to only those who will not compromise security.
* Hardware mechanisms that impose rules on computer programs, thus avoiding depending the computer programs for computer security.
* Operating system mechanisms that impose rules on programs to avoid trusting computer programs.
* Programming strategies to make computer programs dependable and resist subversion.
Secure operating systems

One use of the term computer security refers to technology to implement a secure operating system. Much of this technology is based on science developed in the 1980s and used to produce what may be some of the most impenetrable operating systems ever. Though still valid, the technology is almost inactive today, perhaps because it is complex or not widely understood. Such ultra-strong secure operating systems are based on operating system kernel technology that can guarantee that certain security policies are absolutely enforced in an operating environment. An example of such a Computer security policy is the Bell-LaPadula model. The strategy is based on a coupling of special microprocessor hardware features, often involving the memory management unit, to a special correctly implemented operating system kernel. This forms the foundation for a secure operating system which, if certain critical parts are designed and implemented correctly, can ensure the absolute impossibility of penetration by hostile elements. This capability is enabled because the configuration not only imposes a security policy, but in theory completely protects itself from corruption. Ordinary operating systems, on the other hand, lack the features that assure this maximal level of security. The design methodology to produce such secure systems is precise, deterministic and logical.

Systems designed with such methodology represent the state of the art of computer security and the capability to produce them is not widely known. In sharp contrast to most kinds of software, they meet specifications with verifiable certainty comparable to specifications for size, weight and power. Secure operating systems designed this way are used primarily to protect national security information and military secrets. These are very powerful security tools and very few secure operating systems have been certified at the highest level (Orange Book A-1) to operate over the range of "Top Secret" to "unclassified" (including Honeywell SCOMP, USAF SACDIN, NSA Blacker and Boeing MLS LAN.) The assurance of security depends not only on the soundness of the design strategy, but also on the assurance of correctness of the implementation, and therefore there are degrees of security strength defined for COMPUSEC. The Common Criteria quantifies security strength of products in terms of two components, security capability (as Protection Profile) and assurance levels (as EAL levels.) None of these ultra-high assurance secure general purpose operating systems have been produced for decades or certified under the Common Criteria.

[edit] Security architecture

Security Architecture can be defined as "The design artifacts that describe how the security controls (= security countermeasures) are positioned, and how they relate to the overall IT Architecture. These controls serve the purpose to maintain the system’s quality attributes, among them confidentiality, integrity, availability, accountability and assurance."[1]. In simpler words, a security architecture is the plan that shows where security measures need to be placed. If the plan describes a specific solution then, prior to building such a plan, one would make a risk analysis. If the plan describes a generic high level design then (reference architecture) then the plan should be based on a threat analysis.

[edit] Security by design

The technologies of computer security are based on logic. There is no universal standard notion of what secure behavior is. "Security" is a concept that is unique to each situation. Security is extraneous to the function of a computer application, rather than ancillary to it, thus security necessarily imposes restrictions on the application's behavior.

There are several approaches to security in computing, sometimes a combination of approaches is valid:

1. Trust all the software to abide by a security policy but the software is not trustworthy (this is computer insecurity).
2. Trust all the software to abide by a security policy and the software is validated as trustworthy (by tedious branch and path analysis for example).
3. Trust no software but enforce a security policy with mechanisms that are not trustworthy (again this is computer insecurity).
4. Trust no software but enforce a security policy with trustworthy mechanisms.

Many systems have unintentionally resulted in the first possibility. Approaches one and three lead to failure. Since approach two is expensive and non-deterministic, its use is very limited. Because approach number four is often based on hardware mechanisms and avoid abstractions and a multiplicity of degrees of freedom, it is more practical. Combinations of approaches two and four are often used in a layered architecture with thin layers of two and thick layers of four.

There are myriad strategies and techniques used to design security systems. There are few, if any, effective strategies to enhance security after design.

One technique enforces the principle of least privilege to great extent, where an entity has only the privileges that are needed for its function. That way even if an attacker gains access to one part of the system, fine-grained security ensures that it is just as difficult for them to access the rest.

Furthermore, by breaking the system up into smaller components, the complexity of individual components is reduced, opening up the possibility of using techniques such as automated theorem proving to prove the correctness of crucial software subsystems. This enables a closed form solution to security that works well when only a single well-characterized property can be isolated as critical, and that property is also assessable to math. Not surprisingly, it is impractical for generalized correctness, which probably cannot even be defined, much less proven. Where formal correctness proofs are not possible, rigorous use of code review and unit testing represent a best-effort approach to make modules secure.

The design should use "defense in depth", where more than one subsystem needs to be violated to compromise the integrity of the system and the information it holds. Defense in depth works when the breaching of one security measure does not provide a platform to facilitate subverting another. Also, the cascading principle acknowledges that several low hurdles does not make a high hurdle. So cascading several weak mechanisms does not provide the safety of a single stronger mechanism.

Subsystems should default to secure settings, and wherever possible should be designed to "fail secure" rather than "fail insecure" (see fail safe for the equivalent in safety engineering). Ideally, a secure system should require a deliberate, conscious, knowledgeable and free decision on the part of legitimate authorities in order to make it insecure.

In addition, security should not be an all or nothing issue. The designers and operators of systems should assume that security breaches are inevitable. Full audit trails should be kept of system activity, so that when a security breach occurs, the mechanism and extent of the breach can be determined. Storing audit trails remotely, where they can only be appended to, can keep intruders from covering their tracks. Finally, full disclosure helps to ensure that when bugs are found the "window of vulnerability" is kept as short as possible.
Early history of security by design

The early Multics operating system was notable for its early emphasis on computer security by design, and Multics was possibly the very first operating system to be designed as a secure system from the ground up. In spite of this, Multics' security was broken, not once, but repeatedly. The strategy was known as 'penetrate and test' and has become widely known as a non-terminating process that fails to produce computer security. This led to further work on computer security that prefigured modern security engineering techniques producing closed form processes that terminate.

Health Insurance

2008-03-24T12:53:00.000+07:00

eHealthInsurance is a licensed health insurance agency and the leading online source for individuals, self employed, and small businesses to find, compare and buy Individual Health Insurance, Family Health Insurance, Small Business Health Insurance, Self Employed Health Insurance, and Health Savings Accounts (HSA).

After providing your zip code and some basic information, you'll receive free quotes, compare plans side by side, and apply for coverage online. If you have a question or need personal assistance, you can contact one of our licensed agents for the answers and unbiased advice you need to make the most of your insurance dollars.

Computer Insurance

2008-03-19T10:51:00.000+07:00

When buying a computer it is normal practice to be offered insurance at the point of sale to protect your new purchase. It is now well known that personal computer retailers make a considerable additional profit from customers who believe they are being offered a cheap price. On average electrical retailers are known to charge their customers three to four times more than necessary.

Why Buy Computer Insurance?

Laptops and desktop computers are becoming an increasingly important commodity. For the opportunist thief, your computer is as good as ready money and it is one of the first things to go. This is all too common in business environments, public sector buildings, and now households as well. If you are a consultant who travels with a laptop to business meetings, there is a high risk of your laptop being stolen. Currently, 70,000 computers are stolen each year in the UK, and more than 100,000 are accidentally damaged.

Traditionally, house contents insurance would cover some additional items up to an upper value limit, the items being specified by the owner of the policy. In these circumstances if you have to make a claim, you may be penalised in a number of ways.

Many insurance companies' upper limits are not very high and would not cover the cost of a new computer. Unfortunately computers depreciate quickly and a computer that cost £2,000 when new, might not be worth more than £500 after only a year. Your contents policy would only pay the present value of the computer.
If you make a claim on your contents insurance, your total renewal premium will be significantly higher. This is because the premium is based on the entire contents of your house and not just the item you claimed for.
Many house contents policies will not provide cover if you remove the computer from your house or the office. If you use a laptop and travel to business meetings you are taking an unnecessary risk.

Key Features of Computer Insurance:

'All Risks' cover worldwide.
No excess.
Rapid claims response, with authorisation guaranteed in ordinary circumstances, within 24 hours or less.
No additional security arrangements required.
Simple premium calculation based on the value of your equipment.
All hardware including printers and scanners also covered.
Minimal exclusions.

What is not Covered by Computer Insurance?

As with all technical equipment, computer insurance does not provide cover for items such as:

Maintenance costs.
Electrical or mechanical failure.
Wear and tear.
Fraud and dishonesty.
Consequential loss. Loss or damage caused by sonic bangs is not covered but may be covered under any warranty/extended warranty you may have.

Insurance insulates too much

2008-03-14T09:18:00.000+07:00

Insurance insulates too much

By creating a "security blanket" for its insureds, an insurance company may inadvertently find that its insureds may not be as risk-averse as they might otherwise be (since, by definition, the insured has transferred the risk to the insurer). This problem is known to the insurance industry as moral hazard. To reduce their own financial exposure, insurance companies have contractual clauses that mitigate their obligation to provide coverage if the insured engages in behavior that grossly magnifies their risk of loss or liability.

For example, life insurance companies may require higher premiums or deny coverage altogether to people who work in hazardous occupations or engage in dangerous sports. Liability insurance providers do not provide coverage for liability arising from intentional torts committed by the insured. Even if a provider were so irrational as to desire to provide such coverage, it is against the public policy of most countries to allow such insurance to exist, and thus it is usually illegal.

Closed community self-insurance

Some communities prefer to create virtual insurance amongst themselves by other means than contractual risk transfer, which assigns explicit numerical values to risk. A number of religious groups, including the Amish and some Muslim groups, depend on support provided by their communities when disasters strike. The risk presented by any given person is assumed collectively by the community who all bear the cost of rebuilding lost property and supporting people whose needs are suddenly greater after a loss of some kind. In supportive communities where others can be trusted to follow community leaders, this tacit form of insurance can work. In this manner the community can even out the extreme differences in insurability that exist among its members. Some further justification is also provided by invoking the moral hazard of explicit insurance contracts.

In the United Kingdom The Crown (which, for practical purposes, meant the Civil service) did not insure property such as government buildings. If a government building was damaged, the cost of repair would be met from public funds because, in the long run, this was cheaper than paying insurance premiums. Since many UK government buildings have been sold to property companies, and rented back, this arrangement is now less common and may have disappeared altogether.

Life insurance

2008-03-14T09:16:00.000+07:00

Certain life insurance contracts accumulate cash values, which may be taken by the insured if the policy is surrendered or which may be borrowed against. Some policies, such as annuities and endowment policies, are financial instruments to accumulate or liquidate wealth when it is needed.

Further information: Life insurance

In many countries, such as the U.S. and the UK, the tax law provides that the interest on this cash value is not taxable under certain circumstances. This leads to widespread use of life insurance as a tax-efficient method of saving as well as protection in the event of early death.

In U.S., the tax on interest income on life insurance policies and annuities is generally deferred. However, in some cases the benefit derived from tax deferral may be offset by a low return. This depends upon the insuring company, the type of policy and other variables (mortality, market return, etc.). Moreover, other income tax saving vehicles (e.g., IRAs, 401(k) plans, Roth IRAs) may be better alternatives for value accumulation. A combination of low-cost term life insurance and a higher-return tax-efficient retirement account may achieve better investment return.

Health Insurance

2008-03-13T13:29:00.000+07:00

The term health insurance is generally used to describe a form of insurance that pays for medical expenses. It is sometimes used more broadly to include insurance covering disability or long-term nursing or custodial care needs. It may be provided through a government-sponsored social insurance program, or from private insurance companies. It may be purchased on a group basis (e.g., by a firm to cover its employees) or purchased by individual consumers. In each case, the covered groups or individuals pay premiums or taxes to help protect themselves from high or unexpected healthcare expenses. Similar benefits paying for medical expenses may also be provided through social welfare programs funded by the government.

Health insurance works by estimating the overall risk of healthcare expenses and developing a routine finance structure (such as a monthly premium or annual tax) that will ensure that money is available to pay for the healthcare benefits specified in the insurance agreement. The benefit is administered by a central organization, most often either a government agency or a private or not-for-profit entity operating a health plan.[1]

The concept of health insurance was proposed in 1694 by Hugh the Elder Chamberlen from the Peter Chamberlen family. In the late 19th century, "accident insurance" began to be available, which operated much like modern disability insurance.[2].This payment model continued until the start of the 20th century in some jurisdictions (like California), where all laws regulating health insurance actually referred to disability insurance.[3]

Accident insurance was first offered in the United States by the Franklin Health Assurance Company of Massachusetts. This firm, founded in 1850, offered insurance against injuries arising from railroad and steamboat accidents. Sixty organizations were offering accident insurance in the US by 1866, but the industry consolidated rapidly soon thereafter. While there were earlier experiments, the origins of sickness coverage in the US effectively date from 1890. The first employer-sponsored group disability policy was issued in 1911.[4]

Before the development of medical expense insurance, patients were expected to pay all other health care costs out of their own pockets, under what is known as the fee-for-service business model. During the middle to late 20th century, traditional disability insurance evolved into modern health insurance programs. Today, most comprehensive private health insurance programs cover the cost of routine, preventive, and emergency health care procedures, and also most prescription drugs, but this was not always the case.

Hospital and medical expense policies were introduced during the first half of the 20th century. During the 1920s, individual hospitals began offering services to individuals on a pre-paid basis, eventually leading to the development of Blue Cross organizations.[4] The predecessors of today's Health Maintenance Organizations (HMOs) originated beginning in 1929, through the 1930s and on during World War II.[5][6]

Welcome to Insure and Go Computer and Laptop Insurance Cover

2008-03-10T09:09:00.000+07:00

Insure & Go will ensure that you are not left without computing power for long if your machine should be stolen or damaged. Our computer and laptop insurance cover provides efficient claims handling which enables swift repair or replacement of equipment. Within two hours of receipt of your claim form at our claims office an experienced claims handler will attempt to contact you. The premium is a simple calculation based on the value of your equipment.

Instant laptop and computer insurance quote and cover online insured with leading UK insurance companies

Make Money From Internet

2008-03-05T10:13:00.000+07:00

If you would observe the company that delivers the daily paper to your doorstep for a business case study, you will come to learn that the newspaper publisher hires reporters, writers and other important staff to create the contents and deliver the papers to their readers.

In addition to the above mention, the publisher has to invest regularly in heavy duty machineries and tons of papers in printing tons of newspapers on a daily basis.

And in order to ensure that the newspapers are delivered on time, the publisher appoints agents at every part of the covered territory.

So, how does the newspaper company make money? It is obvious that selling a copy of the papers at less than a dollar would not even be able to even fund the operations.

The answer? Selling advertising spaces! You have definitely seen lots of advertisements in the newspaper. The publisher simply sells advertising space in the papers to advertisers who want to leverage their advertising efforts on the paper’s high readership.

On the same analogy, you can make money the exact way from your newsletter: simply by selling advertising space to prospective advertisers!

If your mailing list size exceeds 1,000 (5,000 is recommended) subscribers and beyond, you can start selling advertising space for say, $10.00 per sponsor ad.

In this manner, you turn every issue you send out to your subscribers into a profit-pulling device. And since there is virtually no end to the stream of advertisers as products, services and businesses are cropping every single day in every industry imaginable, so are your money making opportunities.

Making Money Online buying secrets about adsense of other schemes.

2008-02-26T09:08:00.001+07:00

One aspect of online money making schemes that never fails to amuse me is the ability for people to make money selling "secrets" and "techniques" about specific aspects of making money online.

A few web searches for something like "adsense" will quickly reveal a whole slew of websites offering to sell you secret and never before told tricks about increasing your adsense earnings by extreme amounts.

Now, how on earth can they be secret? If some bloke is out there flogging this PDF file of secret methods for enhancing your adsense earnings, surely this PDF file must be in common circulation on the file-sharing networks? I don't think any serious online money maker is going to have many qualms about pinching somebody else's PDF file.

Additionally, the facts contain within these offers must also be common knowledge on forums and non-fee charging websites. It remains a mystery to be how websites offering these secrets about things like adsense and adwords stay in business.

I suspect part of the reason is good, old-fashioned retail therapy. People are lulled by the fantastic marketing effort made on this sort of website, and, by the time they read to the end of the page, are falling over themselves to find the "buy now" button. They don't stop to think for a moment, and realise that most of the information about enhancing their online money making experience which they are about to part with cash for is probably already available for free in one form or other on the internet.

And these documents don't really contain any top-secret money making information. You are not going to increase your adsense earnings overnight by a factor of ten, because, simply, everybody else is probably doing the same thing!

Like all internet money making ideas, peddling secrets about existing systems like adsense is a lucrative sideline, but, the best techniques for utilizing things like adsense change very fast. I'd imagine the best way of keeping up is to stay in close touch with the forums etc. Any revolutionary information that has found its way into an ebook or whatever, is probably already out of date.

I would very much doubt it is possible to dramatically increase your online money making via adsense simply by buying the book from one of these websites. Surely, if this was possible, the sellers would be busy making money online themselves using these magic secrets?

Well, I think part of the reason is sheer lazyness. It is easy to create one meaningless ebook and keep selling it over and over again. It is much more difficult to build a strong content-rich useful website and earn adwords income from it.

Perhaps if all the people trying to make money out of selling useless adsense facts redirected their efforts into creating useful content rich websites, the internet would be a far better place.

If you would observe the company that delivers the daily paper to your doorstep for a business case study, you will come to learn that the newspaper p

2008-02-26T08:47:00.000+07:00

In addition to the above mention, the publisher has to invest regularly in heavy duty machineries and tons of papers in printing tons of newspapers on a daily basis.

And in order to ensure that the newspapers are delivered on time, the publisher appoints agents at every part of the covered territory.

So, how does the newspaper company make money? It is obvious that selling a copy of the papers at less than a dollar would not even be able to even fund the operations.

On the same analogy, you can make money the exact way from your newsletter: simply by selling advertising space to prospective advertisers!

If your mailing list size exceeds 1,000 (5,000 is recommended) subscribers and beyond, you can start selling advertising space for say, $10.00 per sponsor ad.

Money From Internet

2008-02-22T20:36:00.000+07:00

Maybe you've heard people say that you can get rich on the Internet. But, if you are serious about making money on the Internet, remember, it's not a get rich overnight business. Internet success takes time, effort and knowledge. There's no easy "get rich quick" method, so you need to spend the time for building income stream from your Web site.

You can find many kinds of Web sites that have the aim, directly or indirectly, to make money. Apart from the online retailers who are using their sites to directly make money, you can find many Web sites with various moneymaking features.

Here's an excellent page describing realistic ways of making money on the Internet from your personal Web site - Work From Home. No "get rich quick" schemes. Just proven, reliable ways to to build an online business or use a Web site to expand your offline one.

The basis for building serious income is the high traffic. If your site only gets a few hundred visitors per month, as most of personal Web sites, you'll unlikely make more than pocket change.

Here are some ways of making money on the Internet from your personal Web site...

Banners
They were one of the first ways of making money from hobby Web sites, however they are not so popular now since most surfers don't even look at them. In fact, the click-through rate (the percentage of visitors who actually click on a banner) has steadily dropped, from around 5% 4 years ago to less than 0.5% now.

In the Traffic-Building volume of Make Your Site SELL! 2002 (the free ebook describing all possible ways of making money on the Internet), banners are called #1 "Time and Money Wasters." Save yourself months of poorly spent time. Read this essential manual first.

If you have highly relevant, cleverly designed banners, you can beat the odds. However, you need relatively high traffic to actually make more than pocket change. In fact, most banner advertising companies prefer to only pay for actual sales (even click throughs are no longer attractive, since many people click through because they are paid to, and not because they intend to buy anything).

Freebies
Under this category are things such as free lotto tickets and various games where you can win prizes. Often, these are implemented as pop-ups and are much more annoying than banners.

Affiliate programs
They pay you a percentage of the sales you generate for them, or for each visitor you send. This is one of the best ways of making money on the Internet. You don't have to spend time and energy creating your own product. And some of them pay 50% commission. See Affiliate programs for more information on building income from affiliate programs.

Google AdSense
This is one of the easiest ways of making money on the Internet for small and medium sites by displaying relevant, text-based ads from Google AdWords (Google's own advertising program) and receiving a share of the pay-per-click payment. Sign up for AdSense.

Other tools
There are many tools that can help you make some pretty big commissions without your visitors even realizing that you're building income from their visits.

For example, several search engines will pay you a few cents per search made from your Web site. If a few hundred people use your search box, you'll earn a few dollars a day - not bad for a few minutes of cut & paste a small line of code within the HTML of your Web page.

Selling a Product or Service
This is an obvious way of making money on the Internet. To succeed in it, you have to succeed at three points...

Develop a great product that is of interest to others on the Web.
Write a professional Web site designed to sell.
Attract targeted customers to the site.

Ken Evoy's Make Your Knowledge Sell! is a very useful ebook for those who want to get a piece of the e-commerce pie but don't know how to come up with a product. MYKS! shows you that your knowledge, life experience, specialized interest or hobby can be packaged into an information product ("infoproduct") that other people want and are surfing to find.

An infoproduct offers the best entry point into the world of making money on the Internet for most people. Absolutely everything is in MYKS!... from brainstorming to automating your order-processing. You need absolutely nothing else to succeed at selling what's in your brain.

For additional information on how to start selling online, see Selling on the Internet and Free Merchant Accounts. You'll also find there a list of 3rd party credit card processing companies - processing fees, extra costs and other details.

Money From Internet

2008-02-22T20:23:00.000+07:00

The basis for building serious income is the high traffic. If your site only gets a few hundred visitors per month, as most of personal Web sites, you'll unlikely make more than pocket change.

Here are some ways of making money on the Internet from your personal Web site...

Freebies
Under this category are things such as free lotto tickets and various games where you can win prizes. Often, these are implemented as pop-ups and are much more annoying than banners.

Other tools
There are many tools that can help you make some pretty big commissions without your visitors even realizing that you're building income from their visits.

Selling a Product or Service
This is an obvious way of making money on the Internet. To succeed in it, you have to succeed at three points...

Develop a great product that is of interest to others on the Web.
Write a professional Web site designed to sell.
Attract targeted customers to the site.

See also...

Passive Cashflow Secrets
It's a series of videos in which Neil Shearing shows you examples of how he does work once and then is paid for it over and over again. Each movie comes with a PDF transcript and a set of action steps for you to take.

Internet Success Blueprint
It's a complete guide on how to start making money on the Internet, written specifically for beginners.

Auto Income Secrets
This ebook shows step-by-step how to build websites focused on making money from adverts - gather keywords, build pages around them, place ads and promote the website.

SiteSell Free Downloads
From within this page, you can download several very helpful ebooks, which are highly recommended to those who start making money on the Internet. There's no charge - you're not even asked for your email address

The Difference Between a Virus, Worm and Trojan Horse ?

2008-02-16T02:23:00.000+07:00

The most common blunder people make when the topic of a computer virus arises is to refer to a worm or Trojan horse as a virus. While the words Trojan, worm and virus are often used interchangeably, they are not the same. Viruses, worms and Trojan Horses are all malicious programs that can cause damage to your computer, but there are differences among the three, and knowing those differences can help you to better protect your computer from their often damaging effects.

A computer virus attaches itself to a program or file so it can spread from one computer to another, leaving infections as it travels. Much like human viruses, computer viruses can range in severity: Some viruses cause only mildly annoying effects while others can damage your hardware, software or files. Almost all viruses are attached to an executable file, which means the virus may exist on your computer but it cannot infect your computer unless you run or open the malicious program. It is important to note that a virus cannot be spread without a human action, (such as running an infected program) to keep it going. People continue the spread of a computer virus, mostly unknowingly, by sharing infecting files or sending e-mails with viruses as attachments in the e-mail.

A worm is similar to a virus by its design, and is considered to be a sub-class of a virus. Worms spread from computer to computer, but unlike a virus, it has the capability to travel without any help from a person. A worm takes advantage of file or information transport features on your system, which allows it to travel unaided. The biggest danger with a worm is its capability to replicate itself on your system, so rather than your computer sending out a single worm, it could send out hundreds or thousands of copies of itself, creating a huge devastating effect. One example would be for a worm to send a copy of itself to everyone listed in your e-mail address book. Then, the worm replicates and sends itself out to everyone listed in each of the receiver's address book, and the manifest continues on down the line. Due to the copying nature of a worm and its capability to travel across networks the end result in most cases is that the worm consumes too much system memory (or network bandwidth), causing Web servers, network servers and individual computers to stop responding. In more recent worm attacks such as the much-talked-about .Blaster Worm., the worm has been designed to tunnel into your system and allow malicious users to control your computer remotely. Key Terms To Understanding Computer Viruses:

virus
A program or piece of code that is loaded onto your computer without your knowledge and runs against your wishes.

Trojan Horse
A destructive program that masquerades as a benign application. Unlike viruses, Trojan horses do not replicate themselves

worm
A program or algorithm that replicates itself over a computer network and usually performs malicious actions

blended threat
Blended threats combine the characteristics of viruses, worms, Trojan Horses, and malicious code with server and Internet vulnerabilities .

antivirus program
A utility that searches a hard disk for viruses and removes any that are found.

A Trojan Horse is full of as much trickery as the mythological Trojan Horse it was named after. The Trojan Horse, at first glance will appear to be useful software but will actually do damage once installed or run on your computer. Those on the receiving end of a Trojan Horse are usually tricked into opening them because they appear to be receiving legitimate software or files from a legitimate source. When a Trojan is activated on your computer, the results can vary. Some Trojans are designed to be more annoying than malicious (like changing your desktop, adding silly active desktop icons) or they can cause serious damage by deleting files and destroying information on your system. Trojans are also known to create a backdoor on your computer that gives malicious users access to your system, possibly allowing confidential or personal information to be compromised. Unlike viruses and worms, Trojans do not reproduce by infecting other files nor do they self-replicate.

Added into the mix, we also have what is called a blended threat. A blended threat is a sophisticated attack that bundles some of the worst aspects of viruses, worms, Trojan horses and malicious code into one threat. Blended threats use server and Internet vulnerabilities to initiate, transmit and spread an attack. This combination of method and techniques means blended threats can spread quickly and cause widespread damage. Characteristics of blended threats include: causes harm, propagates by multiple methods, attacks from multiple points and exploits vulnerabilities.

To be considered a blended thread, the attack would normally serve to transport multiple attacks in one payload. For examplem it wouldn't just launch a DoS attack — it would also install a backdoor and damage a local system in one shot. Additionally, blended threats are designed to use multiple modes of transport. For example, a worm may travel through e-mail, but a single blended threat could use multiple routes such as e-mail, IRC and file-sharing sharing networks. The actual attack itself is also not limited to a specific act. For example, rather than a specific attack on predetermined .exe files, a blended thread could modify exe files, HTML files and registry keys at the same time — basically it can cause damage within several areas of your network at one time.

Blended threats are considered to be the worst risk to security since the inception of viruses, as most blended threats require no human intervention to propagate.

Combating Viruses, Worms and Trojan Horses

The first steps to protecting your computer are to ensure your operating system (OS) is up-to-date. This is essential if you are running a Microsoft Windows OS. Secondly, you should have anti-virus software installed on your system and ensure you download updates frequently to ensure your software has the latest fixes for new viruses, worms, and Trojan horses. Additionally, you want to make sure your anti-virus program has the capability to scan e-mail and files as they are downloaded from the Internet. This will help prevent malicious programs from even reaching your computer. You should also install a firewall as well.

A firewall is a system that prevents unauthorized use and access to your computer. A firewall can be either hardware or software. Hardware firewalls provide a strong degree of protection from most forms of attack coming from the outside world and can be purchased as a stand-alone product or in broadband routers. Unfortunately, when battling viruses, worms and Trojans, a hardware firewall may be less effective than a software firewall, as it could possibly ignore embedded worms in out going e-mails and see this as regular network traffic. For individual home users, the most popular firewall choice is a software firewall. A good software firewall will protect your computer from outside attempts to control or gain access your computer, and usually provides additional protection against the most common Trojan programs or e-mail worms. The downside to software firewalls is that they will only protect the computer they are installed on, not a network.

It is important to remember that on its own a firewall is not going to rid you of your computer virus problems, but when used in conjunction with regular operating system updates and a good anti-virus scanning software, it will add some extra security and protection for your computer or network.

Rontokbro aka Brontok Worm

2008-02-14T10:34:00.000+07:00

A mass-mailing email worm that also spreads via USB and thumb drives, the Rontokbro worm - also know as Brontok - takes a multifaceted approach to defy detection and removal. Rontokbro / Brontok modifies the HOSTS file to prevent access to antivirus vendor sites, thereby preventing access to signature updates and online scanners. It may also disable antivirus and other security software running on the system, as well as blocking access to Registry Editor and other system tools needed to attempt manual removal of the worm.

First discovered in late September 2005, as of October 2006 over 20 variants of the Rontokbro / Brontok worm had been discovered. The worm executables often adopt either the Microsoft Word icon or the folder icon. Copies of the worm also often adopt the same name as the folder in which it was dropped. For example, if Rontokbro / Brontok copied itself to a folder named "New Folder", it would do so using the filename "New Folder". Because Windows disables executable file extensions by default, and the worm may use a folder icon, this may make it appear as if the infected file were merely a nested new folder. In addition, the worm typically modifies the Registry to cause the Folder Options menu item to disappear from the Windows Explorer Tools menu.

Some variants of the Rontokbro / Brontok worm cause the system to reboot when certain strings appear in task windows. For example, if "EXE" appears in the title of a window, the worm will cause the system to shutdown and restart. On some occasions, the worm will pause the system during bootup and display a message in a similar fashion to much older DOS viruses. F-Secure includes a screenshot in their Brontok.N write-up.

Rontokbro / Brontok may also launch Ping attacks which, depending on the number of infected systems at any given time, could result in form of a Distributed Denial of Service (DDoS) attack.

Because the worm prevents access to the Registry Editor and other diagnostic tools, and prevents access to antivirus software, removing a Rontokbro / Brontok infection can be tricky. To do so will require access to a second, non-infected PC. Here's how:

From a non-infected PC, follow the first 8 steps outlined in How to Make an F-Prot CD.
Take the F-Prot CD to the infected computer. Boot the infected computer into Safe Mode (see How to Boot into Safe Mode), then follow the 7 remaining steps outlined in the How to Make an F-Prot CD article to scan the system and remove any instances of Rontokbro / Brontok found.
Before rebooting the PC, while still in Safe Mode, disable system restore. You can re-enable the system restore feature later, after you've booted normally, to create a new, clean system restore point.

After cleaning the system, be sure to remove any worm-created entries in the HOSTS file. Then update your antivirus software, test it with the EICAR test file to ensure it's working properly, and rescan your entire system - including any mapped and removable drives.

To prevent reinfection from Rontokbro / Brontok, avoid opening email attachments received unexpectedly - even from someone you know - unless you are certain of the intent. Don't share your USB and thumb drives with others unless you are certain their system is clean and avoid downloading files from anonymous P2P filesharing networks.

Science and Technology Resources on the Internet

2008-02-10T08:37:00.000+07:00

The term computer security is used frequently, but the content of a computer is vulnerable to few risks unless the computer is connected to other computers on a network. As the use of computer networks, especially the Internet, has become pervasive, the concept of computer security has expanded to denote issues pertaining to the networked use of computers and their resources.

The major technical areas of computer security are usually represented by the initials CIA: confidentiality, integrity, and authentication or availability. Confidentiality means that information cannot be access by unauthorized parties. Confidentiality is also known as secrecy or privacy; breaches of confidentiality range from the embarrassing to the disastrous. Integrity means that information is protected against unauthorized changes that are not detectable to authorized users; many incidents of hacking compromise the integrity of databases and other resources. Authentication means that users are who they claim to be. Availability means that resources are accessible by authorized parties; "denial of service" attacks, which are sometimes the topic of national news, are attacks against availability. Other important concerns of computer security professionals are access control and nonrepudiation. Maintaining access control means not only that users can access only those resources and services to which they are entitled, but also that they are not denied resources that they legitimately can expect to access. Nonrepudiation implies that a person who sends a message cannot deny that he sent it and, conversely, that a person who has received a message cannot deny that he received it. In addition to these technical aspects, the conceptual reach of computer security is broad and multifaceted. Computer security touches draws from disciplines as ethics and risk analysis, and is concerned with topics such as computer crime; the prevention, detection, and remediation of attacks; and identity and anonymity in cyberspace.

While confidentiality, integrity, and authenticity are the most important concerns of a computer security manager, privacy is perhaps the most important aspect of computer security for everyday Internet users. Although users may feel that they have nothing to hide when they are registering with an Internet site or service, privacy on the Internet is about protecting one's personal information, even if the information does not seem sensitive. Because of the ease with which information in electronic format can be shared among companies, and because small pieces of related information from different sources can be easily linked together to form a composite of, for example, a person's information seeking habits, it is now very important that individuals are able to maintain control over what information is collected about them, how it is used, who may use it, and what purpose it is used for.

Scope of this Guide

This guide is intended to present a selected list of sites that cover the basic issues of computer security and which provide useful information for the non-expert (librarian, undergraduate student, office manager, etc.) who wants to learn more about this increasingly important subject. The categories are intended to offer points of departure for some of the many aspects of computer security. For the sake of brevity, this guide stops short of entering the vast realm of commercial software products, consulting firms, and the like. The individual who is in the market for security products or services should have no trouble finding descriptions, reviews, and comparisons on the web and through other media.

Methods

The web sites in this list were collected through various methods, including searches of Internet directories such as Google and Yahoo, the Librarian's Index to the Internet, the {Scout Report}, and the World Cat database (userid and password are required); burrowing through information security portals such as InfoSysSec and Packet Storm Security; and exploring links from within quality sites as they were encountered. Emphasis has been placed on sites that provide practical information rather than merely advertise products; accordingly, most of the sites selected are hosted in .edu, .gov, and .org domains. However, commercial sites were not discounted if they provided substantive information in addition to product information.

General Sources

Center for Education and Research in Information Assurance and Security
http://www.cerias.purdue.edu/: CERIAS's mission is to be recognized as the leader in information security and assurance research, education, and community service. To these ends, CERIAS offers a free security seminar on diverse security topics on Wednesday afternoons during the fall and spring semesters; attendees may show up in person or through a live internet stream. The CERIAS web site also includes extensive computer security resources for K-12 teachers, including background information, lesson plans, and links to other web resources.
TECS: The Encyclopedia of Computer Security
http://www.itsecurity.com/: TECS provide a forum for visitors to seek the opinions of one or several security experts on a broad scope of security questions. Users range from individuals asking about their home computers to students working on projects to IT professionals; TECS's panel of volunteer security experts tend to work for computer or security consulting companies. Questions are sent via listserv to the experts, whose answers are then published, along with the question, on the web site. The site owners request that the experts try to provide balanced answers that do not gratuitously advertise specific products; vendors are free to list full product descriptions in the TECS Security Product Database.
CYBERCRIME
http://www.cybercrime.gov/: This site is maintained by the Computer Crime and Intellectual Property Section (CCIPS) of the Criminal Division of the U.S. Department of Justice; the information available at this site is presented from a legal, rather than technical, perspective. It provides a plethora of information about the various ways computers can be used to commit crimes, how and to whom to report computer crimes, and what to do if you are the victim of computer crime. It includes links to cases, laws, legal issues, and policy issues surrounding hacking, intellectual property infringements, and other online offenses.
Common Vulnerabilities and Exposures
http://www.cve.mitre.org/: MITRE, a not-for-profit national resource that provides systems engineering, research and development, and information technology support to the government, has created CVE in an attempt to standardize the names of vulnerabilities and other information security exposures. MITRE's goal is to increase data communication across network tools by encouraging software companies and developers to use the common names found at the CVE web site; according to CERIAS, "CVE is the key to vulnerability database compatibility." To date, over 60 major organizations have agreed to make their products and services CVE compliant.
Stay Safe Online
http://www.staysafeonline.info/: The National Cyber Security Alliance, comprised of corporate and government organization members, sponsors Stay Safe Online to educate home and small business computer users in basic computer security practices, thereby helping to protect the nation's internet infrastructure. The site offers a personal computer security self-test, beginner's guides on various security topics, and a one-hour online course on security fundamentals.
Security Statistics
http://www.securitystats.com/: Because online banks, retailers, and other businesses may wish to protect their reputations by not reporting problems associated with online attacks, statistics about such can be difficult to find. The Security Statistics site is a portal to data on computer security incidents. Statistics are pooled from a wide range of sources, and includes information about security spending, known vulnerabilities, numbers of reported security breaches, economic impact of incidents, arrests and convictions, and more. The site does not guarantee the accuracy of reported statistics, but the sources of each statistic are included.

Ethics

Computer and Information Ethics on WWW
http://www.ethics.ubc.ca/resources/computer/: This site is a subdivision of a website on ethics resources which is maintained by the University of British Columbia's Centre for Applied Ethics. The site provides lists of web sites, as well as lists of electronic and print publications, pertaining to various ethical issues in computing. There is a section on courses in computer ethics, which provides links to online syllabi to classes taught at other institutions, and a list of links to relevant organizations. The breadth of this site is limited, but it's a good place to begin exploring the ethical issues of network computing.
Ethics in Computing
{http://ethics.csc.ncsu.edu//}: This site is administered by Dr. Edward F. Gehringer, an NCSU professor in Electrical & Computer Engineering and Computer Science who teaches several undergraduate and graduate classes in computer science and computer ethics. The site organizes computer ethics into a simple hierarchy of topics, starting with basic information on ethics. The articles are not necessarily recent, although many concepts pertaining to ethics may remain constant over time. An interesting feature is the site map, which looks like a real map, which offers a graphical representation of how the concepts are related.

Privacy

EFF Privacy Now! Campaign
{http://www.eff.org/Privacy/}: The Electronic Frontier Foundation was founded in 1990 to confront civil liberties issues raised by new technologies. EFF's interest in privacy issues runs the gamut from Internet anonymity and pseudonymity to medical privacy to the privacy risks posed by the nation's post-9/11 increased interest in surveillance, biometrics, and a national identification system. This site goes beyond mere tips and offers a thoughtful analysis of the privacy (and social) consequences of our increasingly automated society. Look for Carabella-an interactive adventure game that illustrates some of the privacy and fair use issues associated with online music shopping.
Privacy Rights Clearinghouse
http://www.privacyrights.org/: The Privacy Rights Clearinghouse is a nonprofit consumer advocacy organization. Their web site is full of information on privacy rights in an online environment. The main issues addressed on this site include personal privacy, financial privacy, and identity theft. Information sources include fact sheets covering specific privacy issues, news items and articles about privacy, and transcripts of PRC speeches and testimony from conferences and legislative hearings.
The Privacy Foundation
http://www.privacyfoundation.org/: The Privacy Foundation's main privacy concerns are data that is collected surreptitiously by companies about web surfers and their browsing habits, and employer surveillance of computer activity in the workplace. Users can sign up for free email delivery of the Foundation's TipSheets and Privacy Watch advisories and commentaries. An interesting free download available at this site is Bugnosis, software which alerts Internet Explorer users to web bugs, tiny or invisible web page graphics that have been encoded to collect information about who is browsing the web page.
Platform for Privacy Preferences (P3P) Project
http://www.w3.org/P3P/: The Worldwide Web Consortium, an organization promoting greater interoperability for web technologies, has developed P3P, a proposed standard that allows web sites to state their privacy policies using special keywords so that other P3P-enabled utilities (e.g., web browsers) can interpret them and compare them to a user's privacy preferences. P3P offers users greater control over how their personal information might be used on the Internet by giving them more opportunities to avoid offending sites.

Consumer Information

Better Business Bureau Online
http://www.bbbonline.org/: The Better Business Bureau system, which extends over most of the United States and Canada, has for many years mediated consumer problems by advocating voluntary self-regulation for businesses combined with increased education for consumers. The BBB now extends its services to the e-commerce arena, offering a BBB seal of reliability for qualified businesses to place on their web sites. For consumers, BBBOnline offers a "safe shopping list" of companies which merit the BBB's seal, as well as information on web safety and privacy, and online forms for lodging complaints.
Shopping Safely Online
http://www.cnlnet.org/shoppingonline/index.htm: The National Consumer League offers Shopping Safely Online as part of its larger web site of general consumer information. In addition to online shopping tips, this site provides "e-ssentials" of online privacy and security for the consumer, and advice for using online auctions. Shopping Safely Online provides a link to the NCL's National Fraud Information Center, where users can report suspected fraud and access a wealth of other sources about the risks of doing business online.
Internet Fraud Complaint Center
{http://www.ic3.gov/}: The IFCC, a partnership between the FBI and the National White Collar Crime Center, offers this web site as a place for consumers to learn about Internet fraud, which is largely comprised of incidents relating to online auctions, credit card misuse, and other consumer-related activity. The site provides an easy-to-complete form for reporting Internet fraud. Of special interest is the IFCC's annual report on the numbers, types, and economic impacts of crimes reported through the site.

Kids

NetzSmartz Workshop
http://www.netsmartz.org/: This site is published by the National Center for Missing and Exploited Children. Through games and other online activities, it introduces kids to some of the "outlaws of Webville," and instructs kids on how to respond to inappropriate behavior they might encounter online. The Netsmartz site for parents and educators provides suggestions for online and offline activities and is designed to increase communication between parents and children about Internet safety.
CyberSmart!
{http://www.cybersmart.org/home/}: The CyberSmart! School Program is a non profit corporation that advocates Internet education by empowering children rather than simply monitoring them. The CyberSmart web site provides brief lessons for teens, printable color posters for parents to hang near the family computer, and a curriculum of 65 standards-based lesson plans for K-8 teachers. The curriculum is centered around the SMART model, focusing on safety, manners, advertising, research, and technology. Lessons plans have been designed to stand alone, can be taught in any order, and can be taught by a technology teacher, librarian or media specialist, or science or social studies teacher as appropriate for the subject matter.

Antivirus

Virus Bulletin
http://www.virusbtn.com/: Virus Bulletin is a fee-based, monthly magazine that provides information, reviews, and comparisons of antivirus products. The Virus Bulletin website offers the latest virus-related news, description of recent viruses, and monthly prevalence tables of known virus activity. Consumers can see which antivirus products have earned the VB100% award, which is awarded to products that detect all In The Wild Viruses (see WildList Organization, below) in test scans. Of particular practical use are four step-by-step DOS tutorials for recovering from some of the more common problems of virus infection.
The WildList Organization International
http://www.wildlist.org/: The WildList Organization's mission is "to provide accurate, timely and comprehensive information about 'In the Wild' computer viruses to both users and product developers." "In the wild" viruses are viruses that have been cited by two or more of the organization's panel of computer experts as spreading in the real world and therefore pose a real threat to computers and networks. The WildList is made available free of charge by the organization and is considered a standard against which the effectiveness of antivirus programs is measured. The WildList Organization has retained its independence from any one antivirus developer and encourages all users to find an antivirus vendor and develop a relationship with its customer support service.
Hoax Busters
http://hoaxbusters.ciac.org/: Hoax Busters is a public service of the Department of Energy's Computer Incident Advisory Capability (CIAC). Hoax Busters posits that dealing with hoax emails is annoying and time-consuming at best, and costly at worst. The Hoax Busters web is a clearinghouse of information about various types of Internet hoaxes, and strives to debunk dire warnings about various fake viruses and other malicious code that have no basis in fact. The site also confronts chain letters, urban myths, sympathy letters, and other cons, and offers suggestions for how to recognize hoaxes and what to do about them.
F-Secure: Security Information Center
http://www.f-secure.com/virus-info/: The self described "industry standard source for up-to-date information on new viruses and hoax alerts," this site provides long, easily readable descriptions and screen shots of known viruses, including their variations, and information on how to recover if you're hit. While F-Secure naturally promote the sale of their commercial products, they also offers a few dozen free downloads to fix specific virus problems. Also of interest are a six-minute video entitled "Virus Summary 2001," an account of the most notable (i.e., destructive) virus attacks of 2001, and a list of tips to avoid those pesky, and increasingly popular, email worms.

Security Policies

Security Policy Issues
{http://www.sans.org/rr/whitepapers/policyissues/}: The Systems Administration, Networking, and Security Institute (SANS) is an organization comprised of computer security practitioners from government agencies, corporations, and universities. The SANS reading room provides access to over 1300 research articles across the spectrum of computer security; the Security Policy Issues section features over 60 articles, many of which were written by IT professionals to fulfill part of the requirements for the Global Information Assurance Certification. This site also contains an information security policy primer and policy examples and templates. Access to the SANS reading room is free, but users must register to receive a password.
EDUCAUSE/Cornell Institute for Computer Policy and Law
http://www.educause.edu/icpl/: The ICPL is a collaboration between Cornell, which began its Computer Policy and Law program in 1996, and EDUCAUSE, which promotes intelligent use of information technology in higher education. The Library Resources section provides access to hundreds of computer policies collected from educational institutions of all sorts, companies and corporations, networks, and municipalities. The policies pertain to virtually every aspect of campus technology use, from acceptable/responsible use to library policies to security and privacy policies. Users are invited to submit their own policies to the collection.

Cryptography

Cryptology ePrint Archive
http://eprint.iacr.org/: The International Association for Cryptologic Research (IACR) is a non-profit scientific organization whose purpose is to further research in cryptology and related fields. IACR's Cryptology ePrint Archive accepts clear and readable submissions from authors which "look somewhat new and interesting," and "contain proofs or convincing arguments for any claims." The archive begins in 1996, and as of this writing, there are 136 articles posted for 2002. While many of the newer articles are available as .pdf files, many files are available in postscript format only.
The International PGP Home Page
http://www.pgpi.org/: Pretty Good Privacy (PGP) is a cryptographic device for protecting digital information, including the contents of email messages, developed by Phil Zimmerman in 1991 and distributed as freeware for non-commercial use. The purpose of this web site is to promote the use of PGP worldwide by providing downloads, documentation, FAQs, lists of known bugs, links to web sites, and the latest news and other information about PGP in English and other languages.

Intrusion Detection

DShield-Distributed Intrusion Detection System
http://www.dshield.org/: Dshield.org collects information about cracking, or penetration of computer systems by unauthorized parties, from all over the Internet. Systems administrators are encouraged to share their firewall logs so that patterns of intrusion activity can be analyzed; Dshield will contact an Internet service provider if it appears to be the origin of suspicious activity. Dshield provides a geographic distribution of reported attack sources from the past five days, as well as the IP addresses of the 10 most probed ports and the top 10 offending ports. The site also provides an "Are you cracked?" utility, which compares the user's IP address with a list of known attackers; if an IP address is matched, it is possible that the user's computer has been used by crackers to attack other machines.

Operating System Security

Network Security Library
{http://www.windowsecurity.com/whitepaper/}: This is a site providing articles on general network and system security, and no emphasis is placed on any one OS. Due to the large number of articles available on Unix and Windows, these systems have their own links; articles on other operating systems, such as Macintosh or Linux, can be found through keyword searches. Articles come from a variety of sources, including individual submissions as well as published book chapters. Readers are invited to rate articles on a scale of one to ten, and the average score and number of votes are listed with each article title.
Windows Security Guide
http://www.winguides.com/security/: This site lists security vulnerabilities and fixes for all Microsoft operating systems, as well as for network-related utilities such as MS Internet Explorer and Internet Information Server. Other services include a free newsletter of alerts and updates, and "support forums" for discussion of security topics. There are two levels of membership: the basic free membership allows access to the forums and newsletters, while a fee-based premium subscription option allows access to help files, free downloads, and the ability to turn off advertisements.
Macintosh Security Site
http://www.securemac.com/: The Macintosh Security Site contains several informative articles on Macintosh security, and reviews of many security products for Macs and Mac servers. While the site is supported through paid advertisements, the ads are rather unobtrusive. Of interest is the fact the Macintosh Security Site is maintained as the "white side" of Freak's Macintosh Archive, a "hacking" site devoted to announcing and exploiting security vulnerabilities in Macintosh software & utilities.
Linux Security
http://www.linuxsecurity.com/: This site is sponsored by Guardian Digital, Inc., an Open Source security company which produces EnGarde Linux products. The site is not used solely to advertise EnGarde products, and other vendors and products are represented through their sponsorship of the site as well as in articles and advisories posted at the site. The News section of the site provides full-text articles, reprinted from a variety of external sources, on a wide range of general and Linux-specific security topics; the Documentation section features numerous practical "how-to" articles. Users can subscribe to free weekly Linux security newsletters and advisories and participate in an online mailing list.

Certification

CISSP and SSCP Open Study Guides
http://www.cccure.org/: The International Information Systems Security Certification Consortium, Inc (http://www.isc2.org) offers two security certifications, the Certified Information Systems Security Professional (CISSP) and the Systems Security Certified Practitioner (SSCP). This site offers study guides, tips for taking the certification tests, newsletters, chat rooms, book reviews, and more, all written by volunteers who are preparing for or have passed the exams. Study guides address particular sections included in the exams. Free registration is required to access the full content of this site.

Information Warfare

Information Warfare Site
http://www.iwar.org.uk/: Because of the increasing interconnectedness of critical systems such as telecommunications, banking and finance, energy, and transportation, national infrastructures have become increasingly vulnerable to online terrorist threats. The Information Warfare Site "aims to stimulate debate about a range of subjects from information security to information operations and e-commerce." While the site's domain name denotes United Kingdom, much of the content is derived from government and news sources of the United States and other countries. Online discussion forums cover topics such as e-commerce, terrorism, critical infrastructure protection, and others.

Biometrics

Biometrics Research
http://biometrics.cse.msu.edu/: This site, run by Michigan State University's Department of Computer Science and Engineering, is a good beginning point for learning more about biometrics. It includes a brief but informative overview of biometrics, and descriptions of various biometric technologies, such as fingerprint matching, hand geometry, voice recognition, and so on. The "Projects" and "Publications" lists are limited to work by MSU people, but there is also a short list of external web links leading to biometric companies, consulting firms, and research centers.
International Biometric Group
http://www.ibgweb.com/index.html: International Biometric Group LLC is a biometrics consulting firm which considers itself to be "vendor-independent and technology-neutral, allowing it to objectively and independently assess companies, technologies, products, and projects." Of special interest at IBG's web site is the "Research and Reports" section, where IBG provides information on biometrics basics, specific biometric technologies and their applications, accuracy and performance, as well as vendor and industry information. Users must register with the site to gain access to the full reports, but registration is free and is activated immediately.
Biometrics Catalog
http://www.biometricscatalog.org/: This is a database of biometric technologies maintained by the U.S. Department of Justice. Users can search for information about biometric products by biometric type, keyword, and date, as well as vendor category (commercially available products, products in government testing, products in non-government testing, etc.). Vendors can add information about their products, but forms that do not contain complete contact information will not be posted to the site.

Computer Security

2008-02-10T08:32:00.000+07:00

Computer security is a branch of information security applied to both theoretical and actual computer systems. Computer security is a branch of computer science that addresses enforcement of 'secure' behavior on the operation of computers. The definition of 'secure' varies by application, and is typically defined implicitly or explicitly by a security policy that addresses confidentiality, integrity and availability of electronic information that is processed by or stored on computer systems.

The traditional approach is to create a trusted security kernel that exploits special-purpose hardware mechanisms in the microprocessor to constrain the operating system and the application programs to conform to the security policy. These systems can isolate processes and data to specifier domains and restrict access and privileges of users. This approach avoids trusting most of the operating system and applications.

In addition to restricting actions to a secure subset, a secure system should still permit authorized users to carry out legitimate and useful tasks. It might be possible to secure a computer against misuse using extreme measures:
“ The only truly secure system is one that is powered off, cast in a block of concrete and sealed in a lead-lined room with armed guards - and even then I have my doubts. ”
Eugene H. Spafford, director of the Purdue Center for Education and Research in Information Assurance and Security. [1]

It is important to distinguish the techniques used to increase a system's security from the issue of that system's security status. In particular, systems which contain fundamental flaws[1] in their security designs cannot be made secure without compromising their usability.[citation needed] Most computer systems cannot be made secure even after the application of extensive "computer security" measures. Furthermore, if they are made secure, functionality and ease of use often decreases.

Computer security can also be seen as a subfield of security engineering, which looks at broader security issues in addition to computer security.
Contents
[hide]

* 1 Secure operating systems
* 2 Security by design
o 2.1 Early history of security by design
* 3 Secure coding
* 4 Terms
* 5 Capabilities vs. ACLs
* 6 See also
* 7 Notes
* 8 References
* 9 Further reading
* 10 External links

[edit] Secure operating systems

One use of the term computer security refers to technology to implement a secure operating system. Much of this technology is based on science developed in the 1980s and used to produce what may be some of the most impenetrable operating systems ever. Though still valid, the technology is almost inactive today, perhaps because it is complex or not widely understood. Such ultra-strong secure operating systems are based on operating system kernel technology that can guarantee that certain security policies are absolutely enforced in an operating environment. An example of such a Computer security policy is the Bell-LaPadula model. The strategy is based on a coupling of special microprocessor hardware features, often involving the memory management unit, to a special correctly implemented operating system kernel. This forms the foundation for a secure operating system which, if certain critical parts are designed and implemented correctly, can ensure the absolute impossibility of penetration by hostile elements. This capability is enabled because the configuration not only imposes a security policy, but in theory completely protects itself from corruption. Ordinary operating systems, on the other hand, lack the features that assure this maximal level of security. The design methodology to produce such secure systems is precise, deterministic and logical.

Systems designed with such methodology represent the state of the art of computer security and the capability to produce them is not widely known. In sharp contrast to most kinds of software, they meet specifications with verifiable certainty comparable to specifications for size, weight and power. Secure operating systems designed this way are used primarily to protect national security information and military secrets. These are very powerful security tools and very few secure operating systems have been certified at the highest level (Orange Book A-1) to operate over the range of "Top Secret" to "unclassified" (including Honeywell SCOMP, USAF SACDIN, NSA Blacker and Boeing MLS LAN.) The assurance of security depends not only on the soundness of the design strategy, but also on the assurance of correctness of the implementation, and therefore there are degrees of security strength defined for COMPUSEC. The Common Criteria quantifies security strength of products in terms of two components, security capability (as Protection Profile) and assurance levels (as EAL levels.) None of these ultra-high assurance secure general purpose operating systems have been produced for decades or certified under the Common Criteria.

[edit] Security by design

The technologies of computer security are based on logic. There is no universal standard notion of what secure behavior is. "Security" is a concept that is unique to each situation. Security is extraneous to the function of a computer application, rather than ancillary to it, thus security necessarily imposes restrictions on the application's behavior.

There are several approaches to security in computing, sometimes a combination of approaches is valid:

1. Trust all the software to abide by a security policy but the software is not trustworthy (this is computer insecurity).
2. Trust all the software to abide by a security policy and the software is validated as trustworthy (by tedious branch and path analysis for example).
3. Trust no software but enforce a security policy with mechanisms that are not trustworthy (again this is computer insecurity).
4. Trust no software but enforce a security policy with trustworthy mechanisms.

Many systems unintentionally result in the first possibility. Approaches one and three lead to failure. Since approach two is expensive and non-deterministic, its use is very limited. Because approach number four is often based on hardware mechanisms and avoid abstractions and a multiplicity of degrees of freedom, it is more practical. Combinations of approaches two and four are often used in a layered architecture with thin layers of two and thick layers of four.

There are myriad strategies and techniques used to design security systems. There are few, if any, effective strategies to enhance security after design.

One technique enforces the principle of least privilege to great extent, where an entity has only the privileges that are needed for its function. That way even if an attacker gains access to one part of the system, fine-grained security ensures that it is just as difficult for them to access the rest.

Furthermore, by breaking the system up into smaller components, the complexity of individual components is reduced, opening up the possibility of using techniques such as automated theorem proving to prove the correctness of crucial software subsystems. This enables a closed form solution to security that works well when only a single well-characterized property can be isolated as critical, and that property is also assessable to math. Not surprisingly, it is impractical for generalized correctness, which probably cannot even be defined, much less proven. Where formal correctness proofs are not possible, rigorous use of code review and unit testing represent a best-effort approach to make modules secure.

The design should use "defense in depth", where more than one subsystem needs to be violated to compromise the integrity of the system and the information it holds. Defense in depth works when the breaching of one security measure does not provide a platform to facilitate subverting another. Also, the cascading principle acknowledges that several low hurdles does not make a high hurdle. So cascading several weak mechanisms does not provide the safety of a single stronger mechanism.

Subsystems should default to secure settings, and wherever possible should be designed to "fail secure" rather than "fail insecure" (see fail safe for the equivalent in safety engineering). Ideally, a secure system should require a deliberate, conscious, knowledgeable and free decision on the part of legitimate authorities in order to make it insecure.

In addition, security should not be an all or nothing issue. The designers and operators of systems should assume that security breaches are inevitable. Full audit trails should be kept of system activity, so that when a security breach occurs, the mechanism and extent of the breach can be determined. Storing audit trails remotely, where they can only be appended to, can keep intruders from covering their tracks. Finally, full disclosure helps to ensure that when bugs are found the "window of vulnerability" is kept as short as possible.

[edit] Early history of security by design

The early Multics operating system was notable for its early emphasis on computer security by design, and Multics was possibly the very first operating system to be designed as a secure system from the ground up. In spite of this, Multics' security was broken, not once, but repeatedly. The strategy was known as 'penetrate and test' and has become widely known as a non-terminating process that fails to produce computer security. This led to further work on computer security that prefigured modern security engineering techniques producing closed form processes that terminate.

[edit] Secure coding

If the operating environment is not based on a secure operating system capable of maintaining a domain for its own execution, and capable of protecting application code from malicious subversion, and capable of protecting the system from subverted code, then high degrees of security are understandably not possible. While such secure operating systems are possible and have been implemented, most commercial systems fall in a 'low security' category because they rely on features not supported by secure operating systems (like portability, et al.). In low security operating environments, applications must be relied on to participate in their own protection. There are 'best effort' secure coding practices that can be followed to make an application more resistant to malicious subversion.

In commercial environments, the majority of software subversion vulnerabilities result from a few known kinds of coding defects. Common software defects include buffer overflows, format string vulnerabilities, integer overflow, and code/command injection.

Some common languages such as C and C++ are vulnerable to all of these defects (see Seacord, "Secure Coding in C and C++"). Other languages, such as Java, are more resistant to some of these defects, but are still prone to code/command injection and other software defects which facilitate subversion.

Recently another bad coding practise has come under scrutiny; dangling pointers. The first known exploit for this particular problem was presented in July 2007. Before this publication the problem was known but considered to be academic and not practically exploitable. [2]

In summary, 'secure coding' can provide significant payback in low security operating environments, and therefore worth the effort. Still there is no known way to provide a reliable degree of subversion resistance with any degree or combination of 'secure coding.'

[edit] Terms

The following terms used in engineering secure systems are explained below.

* Firewall Firewalls can either be hardware devices or software programs. They provide some protection from online intrusion, but since they allow some applications (e.g. web browsers) to connect to the Internet, they don't protect against some unpatched vulnerabilities in these applications (e.g. lists of known unpatched holes from Secunia and SecurityFocus).

* Automated theorem proving and other verification tools can enable critical algorithms and code used in secure systems to be mathematically proven to meet their specifications.
* Thus simple microkernels can be written so that we can be sure they don't contain any bugs: eg EROS and Coyotos.

A bigger OS, capable of providing a standard API like POSIX, can be built on a microkernel using small API servers running as normal programs. If one of these API servers has a bug, the kernel and the other servers are not affected: e.g. Hurd.

* Cryptographic techniques can be used to defend data in transit between systems, reducing the probability that data exchanged between systems can be intercepted or modified.
* Strong authentication techniques can be used to ensure that communication end-points are who they say they are.

Secure cryptoprocessors can be used to leverage physical security techniques into protecting the security of the computer system.

* Chain of trust techniques can be used to attempt to ensure that all software loaded has been certified as authentic by the system's designers.
* Mandatory access control can be used to ensure that privileged access is withdrawn when privileges are revoked. For example, deleting a user account should also stop any processes that are running with that user's privileges.
* Capability and access control list techniques can be used to ensure privilege separation and mandatory access control. The next sections discuss their use.

Some of the following items may belong to the computer insecurity article:

* Do not run an application with known security flaws. Either leave it turned off until it can be patched or otherwise fixed, or delete it and replace it with some other application. Publicly known flaws are the main entry used by worms to automatically break into a system and then spread to other systems connected to it. The security website Secunia provides a search tool for unpatched known flaws in popular products.

Cryptographic techniques involve transforming information, scrambling it so it becomes unreadable during transmission. The intended recipient can unscramble the message, but eavesdroppers cannot.
Cryptographic techniques involve transforming information, scrambling it so it becomes unreadable during transmission. The intended recipient can unscramble the message, but eavesdroppers cannot.

* Backups are a way of securing information; they are another copy of all the important computer files kept in another location. These files are kept on hard disks, CD-Rs, CD-RWs, and tapes. Suggested locations for backups are a fireproof, waterproof, and heat proof safe, or in a separate, offsite location than that in which the original files are contained. Some individuals and companies also keep their backups in safe deposit boxes inside bank vaults. There is also a fourth option, which involves using one of the file hosting services that backs up files over the Internet for both business and individuals.
o Backups are also important for reasons other than security. Natural disasters, such as earthquakes, hurricanes, or tornadoes, may strike the building where the computer is located. The building can be on fire, or an explosion may occur. There needs to be a recent backup at an alternate secure location, in case of such kind of disaster. The backup needs to be moved between the geographic sites in a secure manner, so as to prevent it from being stolen.
* Anti-virus software consists of computer programs that attempt to identify, thwart and eliminate computer viruses and other malicious software (malware).
* Firewalls are systems which help protect computers and computer networks from attack and subsequent intrusion by restricting the network traffic which can pass through them, based on a set of system administrator defined rules.
* Access authorization restricts access to a computer to group of users through the use of authentication systems. These systems can protect either the whole computer - such as through an interactive logon screen - or individual services, such as an FTP server. There are many methods for identifying and authenticating users, such as passwords, identification cards, and, more recently, smart cards and biometric systems.
* Encryption is used to protect the message from the eyes of others. It can be done in several ways by switching the characters around, replacing characters with others, and even removing characters from the message. These have to be used in combination to make the encryption secure enough, that is to say, sufficiently difficult to crack. Public key encryption is a refined and practical way of doing encryption. It allows for example anyone to write a message for a list of recipients, and only those recipients will be able to read that message.
* Intrusion-detection systems can scan a network for people that are on the network but who should not be there or are doing things that they should not be doing, for example trying a lot of passwords to gain access to the network.
* Pinging The ping application can be used by potential hackers to find if an IP address is reachable. If a hacker finds a computer they can try a port scan to detect and attack services on that computer.
* Social engineering awareness - Keeping employees aware of the dangers of social engineering and/or having a policy in place to prevent social engineering can reduce successful breaches of the network and servers.
* Honey pots are computers that are either intentionally or unintentionally left vulnerable to attack by hackers. They can be used to catch hackers or fix vulnerabilities.

Turn Your Computer Into a Cash Machine and Make Money

2008-02-04T14:15:00.000+07:00

There are hundreds of stories about ambitious people who quit their jobs to start businesses in their garages, worked 80-hour weeks, sold their companies and wound up rich. This isn't one of them.

Instead, this is about the growing number of average people who are spending their leisure hours selling hobbies and services on home computers and the Internet. With full-time salaries stretched thin and the cost of necessities rising, more people are looking for low-risk ways to earn extra income.

"The Web is a great place to shop and spend money, but it's pretty great for making money too," says Joanne Pratt, a Dallas-based adviser to the Small Business Administration on at-home commerce.

More than half of all small businesses are based at home, according to the SBA. "Computers, Internet access, cell-phone technology and simplified web-page design software have all become cheaper and faster in recent years, making it easier to launch some type of at-home enterprise without sinking a lot of money into it," says Simon Yates, senior analyst at Forrester Research.

Most people who run an at-home business use a desktop computer, connect to the Internet and live in a household where the average annual income is $65,000, reports Forrester. To manage the extra cash, many entrepreneurs are using accounting software programs for small businesses, such as Intuit's QuickBooks line, which generated revenue of $654 million last year -- a jump of nearly 100 percent since 2000.

"If you're the slightest bit entrepreneurial, you can reach large numbers of consumers instantly over the Internet, while key-word searches at Google let consumers reach you just as quickly," says Pratt. "The Web is an amazing marketplace." How can you turn your PC into a cash machine? It's easier than you think:

Auction Stuff on eBay
In New York, where trend-conscious executives and socialites routinely clear out cramped apartment closets to make room for newer looks, Bonnie Levine is considered something of a personal seller. Think Carrie Bradshaw in reverse. When the Manolo Blahniks and Pradas have to go, Levine gets a call to pick them up.

At home, Levine, 41, and her partner, Mindy Calo, 34, auction off the shoes, designer clothes and accessories on eBay, taking 50 percent of all sales. "We're both moms and our husbands work full-time," says Levine. "We do this to earn extra money between family chores, not to get rich quick."

Levine and Calo devote about 20 hours a week to their e-enterprise, and each pockets about $3,000 a month. The idea for the business came to Calo in 2003 when she auctioned off some of her own clothes. Soon Calo and Levine were doing the same for families and friends nationwide, using the eBay seller name Mindycara. In fact, there are now more than 50,000 "trading assistants" registered with eBay to help people auction off their goods.

"Both of us knew high-powered women with great taste, and they told other women, who told their circle of friends," says Levine. Now the pair has 20 regular clients.

In addition to sorting through clothes, Levine and Calo snap digital images, write up descriptions, determine market values using andale.com, post the information on eBay, and ship merchandise to winning bidders.

To avoid paper clutter, they use channeladvisor.com, a virtual office that stores images, e-mails and documents they don't want to print out or can't afford to lose in a computer crash.

Levine and Calo's advice: Focus on satisfying your customers. "If you have a '500' positive feedback rating," says Calo, "you're much more likely to be viewed as reliable and trustworthy, which counts for everything on eBay."

Blog for $$$
When he's not teaching Internet and constitutional law full-time at the University of Tennessee, Glenn Reynolds, 44, can be found "blogging" on his computer.

Reynolds, creator of the conservative instapundit.com, is one of a growing number of bloggers (blog is short for web log) who post commentary, reviews, photos and more on a wide range of topics on websites throughout the day. Imagine a cyberspace soapbox, and you get the idea.

Blogging is something of a Seinfeld experience -- enabling anyone with a website to write about nothing and everything on a regular basis and receive feedback from readers. What did you do today? That's a blog. What do you think about today's headlines? That's a blog too. How's your pet chinchilla doing? Another blog. "It's like your own printing press, without having to worry about paper, ink or postage," says Reynolds.

Technorati.com, a San Francisco-based real-time search engine that tracks web logs, estimates that 12,000 new blogs are created each day. They range from engadget.com, which features consumer electronics news and reviews, to boingboing.net, with posts on everything from spring-loaded women's shoes to novelty records.

To attract and hold a large, well-defined audience that advertisers will want to reach, a blogger needs a strong point of view, an engaging writing style and a gift for smart analysis. Reynolds says his site receives up to 500,000 visits daily and earns income -- $3,000 a month -- through contributions and posted ads.

"I put a tip jar on my site in 2002 after a friend suggested it," he says. "I thought it was a dumb idea, but I earned $1,300 in the first few days."

Last year, instapundit.com generated so much daily traffic that blogads.com, an Internet ad-sales company, convinced Reynolds to accept ads on his site. Blogads.com takes 20 percent of the fee paid by advertisers.

Reynolds devotes two to three hours a day -- between classes and at night -- writing entries and reviewing upward of 200 e-mails. "When your site generates enough buzz, you start getting great links and opinions from others that you can post," says Reynolds. "At this point, my site is almost a group blog with a strong editor."

Does Reynolds dream about giving up teaching and blogging full-time? "This is just a hobby, not my life's work," he says. "The only difference between this and my other hobbies, like scuba diving, is that blogging makes a little money." Reynolds's advice: Keep it fresh "so your audience will keep coming back."

Forecast the Future
Emily Galash's friends are so jealous. The 16-year-old Portland, Oregon, high school sophomore is paid $125 a month to take digital photos of teen culture and send them to Look-Look, a youth-culture marketing and trend-forecasting firm in Hollywood.

Galash is one of Look-Look's 35,000 teen trendspotters worldwide who feed their network inside information about the ever-shifting tastes of the lucrative youth market. The demand for hip, sharp-eyed trendspotters is growing as companies and consultancies attempt to learn more about what makes teens buy.

Some of Look-Look's corporate clients, such as Virgin Mobile, a cell-phone service provider, use the images on their websites to give pages an authentic teen feel. Which is why Galash's subjects must first agree to be photographed and then sign a release before she can upload their images to look-look.com.

Galash was offered a shot as a trendspotter last August, when her cousin gave up the job. Known at Look-Look as a "photojournalist," Galash finds her best subjects at school, in the park, at local malls and near the city's many music clubs. "It's getting more difficult to capture original styles because so many young people work hard to stand out," says Galash. "You have to be able to spot the difference between someone who's copying trends and someone who's truly inventing a new look."

Galash's advice: Develop your communication skills and intuitive feel for that next cool thing. But remember that "schoolwork comes first."

Sell Your Hobby
Stephanie Sorbel is one of only a handful of Kyle, South Dakota, residents who own a computer. She's also one of only a few members of the Oglala Lakota tribe on the Pine Ridge Reservation who sell traditional clothes and crafts on the Internet.

Word-of-mouth sales from Sorbel's site (lakotamall.com/lakotadreams) bring in an extra $1,500 a month, which along with her and her husband's full-time salaries goes to support their four children.

Sorbel taught herself to use the computer and navigate the Internet after her Marine husband bought her a PC in 1997 to e-mail him while he was stationed in California. When her mother suggested she sell her crafts on the Internet, Sorbel applied for a low-interest loan from the Lakota Fund, which helps businesses develop on the reservation. Then Sorbel was able to hire a website designer and pay a hosting service. "People don't realize how many funds there are that can help you start a website," says Sorbel, who now works as an office manager for the fund.

Sorbel made her first online dollar in 1999 when a craft shop commissioned a traditional cradleboard for $800. "They sold it right away and immediately asked me to make a doll and other items," she says.

Using traditional 18th-century techniques passed down to her by tribal members, Sorbel decorates clothes by pressing porcupine quills flat and hand-sewing them, using deer or buffalo tendon.

Time management is key. "After we eat dinner each night, I work on my projects in the same room where my children are doing their homework," she says. "When they're done, my 12-year-old daughter helps with the beadwork, while the others put hair on the beaded dolls."

Sorbel works on several projects simultaneously. The men's powwow dance leggings ($1,500) she's completing will take a couple of months, while the $700 doll of Standing Bear, one of her husband's ancestors, will require weeks. Sorbel's advice: Be sure visitors to your site don't have to hunt to find a phone number or e-mail address for you. Feature up-close images of your products. Most important, she says, "Never over-promise customers, and always be honest about what you can and can't do within their time frame."

Troubleshoot PCs
After years spent fixing their kids' computers, Donna Gaynor and Maria Luskin decided they could earn extra income doing just that for people in their San Diego neighborhood. So they took classes to become certified through the Computing Technology Industry Association (comptia.com), an international IT trade organization.

In 2002, Gaynor and Luskin formed PC Divas, a mini-business that brings in about $3,000 a month. They try to work no more than 20 hours a week -- usually from 10 a.m. to 2 p.m. while their teenage children are in high school.

"We called ourselves PC Divas so we'd always remember that this is a side venture and that we have families and lives," says Gaynor, laughing. They have about 250 clients, charge $75 an hour, and limit repairs to computers within a 10-minute radius of their homes.

A growing part of their business is diagnosing problems remotely -- provided the client has Windows XP. With the client's permission, Gaynor and Luskin use software that lets them see the customer's desktop from their home computer and even control the client's mouse to resolve problems.

"We have a client in his 70s who regularly calls to say he can't find a file or that his computer is acting strange," says Luskin. "I connect to his PC while he's sitting in front of it, and I use his cursor to show him what's wrong or where a file is located. It freaks him out a little -- it's like watching a piano play by itself -- but we're on the phone together and he trusts me."

Gaynor and Luskin's advice: Review a service contract from a major computer-repair company and use it as a model. Then have a lawyer draw up a tailor-made contract that advises the customer of the risk to his data and limits your responsibility to the agreed-upon repair. It should also specify a time limit to any guarantee of your work. "We make our own schedules; we work only a few hours a day and provide good service," says Gaynor. "We're computer divas."

Routers

2008-01-30T20:42:00.000+07:00

Definition: Routers are physical devices that join multiple wired or wireless networks together. Technically, a wired or wireless router is a Layer 3 gateway, meaning that the wired/wireless router connects networks (as gateways do), and that the router operates at the network layer of the OSI model.

Home networkers often use an Internet Protocol (IP) wired or wireless router, IP being the most common OSI network layer protocol. An IP router such as a DSL or cable modem broadband router joins the home's local area network (LAN) to the wide-area network (WAN) of the Internet.

By maintaining configuration information in a piece of storage called the "routing table," wired or wireless routers also have the ability to filter traffic, either incoming or outgoing, based on the IP addresses of senders and receivers.Some routers allow the home networker to update the routing table from a Web browser interface. Broadband routers combine the functions of a router with those of a network switch and a firewall in a single unit.

State VoIP

2008-01-30T20:40:00.001+07:00

Access to 911 and emergency services is an issue that affects us at all levels - national, state, and local. Therefore, the FCC and the National Association of Regulatory Utility Commissioners ("NARUC") formed the Joint Federal/State VoIP Enhanced 911 Enforcement Task Force to facilitate compliance with and enforcement of the FCC’s VoIP 911 rules. The Task Force, which consists of staff from the FCC and State Public Utility Commissions, will coordinate closely with the National Emergency Number Association, the Association of Public Safety Communications Officials, and state and local 911 authorities. The Task Force’s mission is to develop educational materials to ensure that consumers understand their rights and the requirements of the FCC’s VoIP 911 Order; develop appropriate compliance and enforcement strategies; compile data; and share best practices.

VoiP

2008-01-30T20:39:00.001+07:00

Since Americans were first able to dial "9-1-1" to reach emergency services in 1965, the public increasingly has come to depend on 911 in times of crisis. The communications industry, the states, and the Federal Communications Commission ("FCC") have worked hard to ensure that 911 is almost universally available on traditional wireline and wireless phones so that the public has access to emergency services. Telecommunications capabilities have advanced considerably since 1965. Most wireline 911 service has been enhanced ("E911") with the ability to provide caller identification and location information to the call answering center ("E911") and the FCC has established a program to require wireless telephone carriers to provide E911 capability. Not long ago, however, the states and the FCC began to recognize that consumers may not always understand that E911 and basic 911 services may work differently - or not at all - over Voice over Internet Protocol ("VoIP") services. Because in many cases, VoIP services operate much like traditional telephone service, including the capability to make calls to and receive calls from users on the traditional telephone network, some customers assume that these services also offer comparable access to 911 services.

In May 2005, the FCC adopted rules that respond to the threat that such misunderstandings pose to public safety. The FCC adopted rules requiring providers of interconnected VoIP services to supply 911 emergency calling capabilities to their customers as a mandatory feature of the service by November 28, 2005. "Interconnected" VoIP services are VoIP services that allow a user generally to receive calls from and make calls to the traditional telephone network. Under the FCC rules, interconnected VoIP providers must:

Deliver all 911 calls to the local emergency call center;
Deliver the customer’s call back number and location information where the emergency call center is capable of receiving it; and
Inform their customers of the capabilities and limitations of their VoIP 911 service.

Frequently Asked Questions

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How VoIP / Internet Voice Works
VoIP services convert your voice into a digital signal that travels over the Internet. If you are calling a regular phone number, the signal is converted to a regular telephone signal before it reaches the destination. VoIP can allow you to make a call directly from a computer, a special VoIP phone, or a traditional phone connected to a special adapter. In addition, wireless "hot spots" in locations such as airports, parks, and cafes allow you to connect to the Internet and may enable you to use VoIP service wirelessly.

What Kind of Equipment Do I Need?
A broadband (high speed Internet) connection is required. This can be through a cable modem, or high speed services such as DSL or a local area network. A computer, adaptor, or specialized phone is required. Some VoIP services only work over your computer or a special VoIP phone, while other services allow you to use a traditional phone connected to a VoIP adapter. If you use your computer, you will need some software and an inexpensive microphone. Special VoIP phones plug directly into your broadband connection and operate largely like a traditional telephone. If you use a telephone with a VoIP adapter, you'll be able to dial just as you always have, and the service provider may also provide a dial tone.

Is there a difference between making a Local Call and a Long Distance Call?

Some VoIP providers offer their services for free, normally only for calls to other subscribers to the service. Your VoIP provider may permit you to select an area code different from the area in which you live. It also means that people who call you may incur long distance charges depending on their area code and service.

Some VoIP providers charge for a long distance call to a number outside your calling area, similar to existing, traditional wireline telephone service. Other VoIP providers permit you to call anywhere at a flat rate for a fixed number of minutes.

If I have VoIP service, who can I call?
Depending upon your service, you might be limited only to other subscribers to the service, or you may be able to call anyone who has a telephone number - including local, long distance, mobile, and international numbers. If you are calling someone who has a regular analog phone, that person does not need any special equipment to talk to you. Some VoIP services may allow you to speak with more than one person at a time.

What Are Some Advantages of VoIP?
Some VoIP services offer features and services that are not available with a traditional phone, or are available but only for an additional fee. You may also be able to avoid paying for both a broadband connection and a traditional telephone line.

What Are Some disadvantages of VoIP?
If you're considering replacing your traditional telephone service with VoIP, there are some possible differences:

Some VoIP services don't work during power outages and the service provider may not offer backup power.
Not all VoIP services connect directly to emergency services through 9-1-1. For additional information, see www.voip911.gov.
VoIP providers may or may not offer directory assistance/white page listings.

Can I use my Computer While I talk on the Phone?
In most cases, yes.

Can I Take My Phone Adapter with me When I Travel?
Some VoIP service providers offer services that can be used wherever a high speed Internet connection available. Using a VoIP service from a new location may impact your ability to connect directly to emergency services through 9-1-1. For additional information, see www.voip911.gov.

Does my Computer Have to be Turned on?
Only if your service requires you to make calls using your computer. All VoIP services require your broadband Internet connection to be active.

How Do I Know If I have a VoIP phone Call?
If you have a special VoIP phone or a regular telephone connected to a VoIP adapter, the phone will ring like a traditional telephone. If your VoIP service requires you to make calls using your computer, the software supplied by your service provider will alert you when you have an incoming call.

Does the FCC Regulate VoIP?
In June 2005 the FCC imposed 911 obligations on providers of “interconnected” VoIP services – VoIP services that allow users generally to make calls to and receive calls from the regular telephone network. You should know, however, that 911 calls using VoIP are handled differently than 911 calls using your regular telephone service. Please see our consumer fact sheet on VoIP and 911 services at www.voip911.gov for complete information on these differences.

In addition, the FCC requires interconnected VoIP providers to comply with the Communications Assistance for Law Enforcement Act of 1994 (CALEA) and to contribute to the Universal Service Fund, which supports communications services in high-cost areas and for income-eligible telephone subscribers.

Aspects of these considerations may change with new developments in internet technology. You should always check with the VoIP service provider you choose to confirm any advantages and limitations to their service.

Area Network

2008-01-30T19:22:00.001+07:00

One way to categorize the different types of computer network designs is by their scope or scale. For historical reasons, the networking industry refers to nearly every type of design as some kind of area network. Common examples of area network types are:

LAN - Local Area Network
WLAN - Wireless Local Area Network
WAN - Wide Area Network
MAN - Metropolitan Area Network
SAN - Storage Area Network, System Area Network, Server Area Network, or sometimes Small Area Network
CAN - Campus Area Network, Controller Area Network, or sometimes Cluster Area Network
PAN - Personal Area Network
DAN - Desk Area Network

LAN and WAN were the original categories of area networks, while the others have gradually emerged over many years of technology evolution.

Note that these network types are a separate concept from network topologies such as bus, ring and star.

Introduction to Network Topologies

LAN - Local Area Network

A LAN connects network devices over a relatively short distance.A networked office building, school, or home usually contains a single LAN, though sometimes one building will contain a few small LANs (perhaps one per room), and occasionally a LAN will span a group of nearby buildings. In TCP/IP networking, a LAN is often but not always implemented as a single IP subnet.

In addition to operating in a limited space, LANs are also typically owned, controlled, and managed by a single person or organization. They also tend to use certain connectivity technologies, primarily Ethernet and Token Ring.

WAN - Wide Area Network

As the term implies, a WAN spans a large physical distance. The Internet is the largest WAN, spanning the Earth.

A WAN is a geographically-dispersed collection of LANs. A network device called a router connects LANs to a WAN. In IP networking, the router maintains both a LAN address and a WAN address.

A WAN differs from a LAN in several important ways. Most WANs (like the Internet) are not owned by any one organization but rather exist under collective or distributed ownership and management. WANs tend to use technology like ATM, Frame Relay and X.25 for connectivity over the longer distances.

LAN, WAN and Home Networking

Residences typically employ one LAN and connect to the Internet WAN via an Internet Service Provider (ISP) using a broadband modem. The ISP provides a WAN IP address to the modem, and all of the computers on the home network use LAN (so-called private) IP addresses. All computers on the home LAN can communicate directly with each other but must go through a central gateway, typically a broadband router, to reach the ISP.

2008-01-30T19:22:00.000+07:00

LAN - Local Area Network
WLAN - Wireless Local Area Network
WAN - Wide Area Network
MAN - Metropolitan Area Network
SAN - Storage Area Network, System Area Network, Server Area Network, or sometimes Small Area Network
CAN - Campus Area Network, Controller Area Network, or sometimes Cluster Area Network
PAN - Personal Area Network
DAN - Desk Area Network

LAN and WAN were the original categories of area networks, while the others have gradually emerged over many years of technology evolution.

Note that these network types are a separate concept from network topologies such as bus, ring and star.

Introduction to Network Topologies

LAN - Local Area Network

WAN - Wide Area Network

As the term implies, a WAN spans a large physical distance. The Internet is the largest WAN, spanning the Earth.

A WAN is a geographically-dispersed collection of LANs. A network device called a router connects LANs to a WAN. In IP networking, the router maintains both a LAN address and a WAN address.

LAN, WAN and Home Networking

Computer network

2008-01-29T16:22:00.000+07:00

By scale

Computer networks may be classified according to the scale: Personal area network (PAN), Local Area Network (LAN), Campus Area Network (CAN), Metropolitan area network (MAN), or Wide area network (WAN). As Ethernet increasingly is the standard interface to networks, these distinctions are more important to the network administrator than the end user. Network administrators may have to tune the network, based on delay that derives from distance, to achieve the desired Quality of Service (QoS). The primary difference in the networks is the size.

Controller Area Networks are a special niche, as in control of a vehicle's engine, a boat's electronics, or a set of factory robots.

[edit] By connection method

Computer networks may be classified according to the hardware technology that is used to connect the individual devices in the network such as Optical fiber, Ethernet, Wireless LAN, HomePNA, or Power line communication.

Ethernets use physical wiring to connect devices. Often, they employ the use of hubs, switches, bridges, and routers.

Wireless LAN technology is built to connect devices without wiring. These devices use a radio frequency to connect.

[edit] By functional relationship (Network Architectures)

Computer networks may be classified according to the functional relationships which exist between the elements of the network, for example Active Networking, Client-server and Peer-to-peer (workgroup) architectures.

[edit] By network topology

Main article: Network Topology

Computer networks may be classified according to the network topology upon which the network is based, such as Bus network, Star network, Ring network, Mesh network, Star-bus network, Tree or Hierarchical topology network, etc.

Network Topology signifies the way in which intelligent devices in the network see their logical relations to one another. The use of the term "logical" here is significant. That is, network topology is independent of the "physical" layout of the network. Even if networked computers are physically placed in a linear arrangement, if they are connected via a hub, the network has a Star topology, rather than a Bus Topology. In this regard the visual and operational characteristics of a network are distinct; the logical network topology is not necessarily the same as the physical layout.

[edit] By protocol

Computer networks may be classified according to the communications protocol that is being used on the network. See the articles on List of network protocol stacks and List of network protocols for more information. For a development of the foundations of protocol design see Srikant 2004 ^[1] and Meyn 2007 ^[2]

[edit] Types of networks:

Below is a list of the most common types of computer networks in order of scale.

[edit] Personal Area Network (PAN)

Main article: Personal area network

A personal area network (PAN) is a computer network used for communication among computer devices close to one person. Some examples of devices that may be used in a PAN are printers, fax machines, telephones, PDAs or scanners. The reach of a PAN is typically within about 20-30 feet (approximately 4-6 Meters). PANs can be used for communication among the individual devices (intrapersonal communication), or for connecting to a higher level network and the Internet (an uplink).

Personal area networks may be wired with computer buses such as USB and FireWire. A wireless personal area network (WPAN) can also be made possible with network technologies such as IrDA and Bluetooth.

[edit] Local Area Network (LAN)

Main article: Local Area Network

A network covering a small geographic area, like a home, office, or building. Current LANs are most likely to be based on Ethernet technology. For example, a library will have a wired or wireless LAN for users to interconnect local devices (e.g., printers and servers) connect to the internet. All of the PCs in the library are connected by category 5 (Cat5) cable, running the IEEE 802.3 protocol through a system of interconnection devices and eventually connect to the internet. The cables to the servers are on Cat 5e enhanced cable, which will support IEEE 802.3 at 1 Gbps.

The staff computers (bright green) can get to the color printer, checkout records, and the academic network and the Internet. All user computers can get to the Internet and the card catalog. Each workgroup can get to its local printer. Note that the printers are not accessible from outside their workgroup.

Typical library network, in a branching tree topology and controlled access to resources

All interconnected devices must understand the network layer (layer 3), because they are handling multiple subnets (the different colors). Those inside the library, which have only 10/100 Mbps Ethernet connections to the user device and a Gigabit Ethernet connection to the central router, could be called "layer 3 switches" because they only have Ethernet interfaces and must understand IP. It would be more correct to call them access routers, where the router at the top is a distribution router that connects to the Internet and academic networks' customer access routers.

The staff have a VoIP network that also connects to both the Internet and the academic network. They could have paths to the central library system telephone switch, via the academic network. Since voice must have the highest priority, it is on the pink network. The VoIP protocols used, such as RSVP, are virtual circuits rather than connectionless forwarding paths.

Depending on the circumstance, the computers in the network might be connected using cables and hubs. Other networks might be connected strictly wirelessly. It depends on the number of PCs that you are trying to connect, the physical layout of your workspace, and the various needs of network. Not shown in this diagram, for example, is a wireless workstation used when shelving books.

The defining characteristics of LANs, in contrast to WANs (wide area networks), include their much higher data transfer rates, smaller geographic range, and lack of a need for leased telecommunication lines. Current Ethernet or other IEEE 802.3 LAN technologies operate at speeds up to 10 Gbit/s. This is the data transfer rate. IEEE has projects investigating the standardization of 100 Gbit/s, and possibly 40 Gbit/s. Inverse multiplexing is commonly used to build a faster aggregate from slower physical streams, such as bringing 4 Gbit/s aggregate stream into a computer or network element with four 1 Gbit/s interfaces.

[edit] Campus Area Network (CAN)

Main article: Campus Area Network

A network that connects two or more LANs but that is limited to a specific and contiguous geographical area such as a college campus, industrial complex, or a military base. A CAN, may be considered a type of MAN (metropolitan area network), but is generally limited to an area that is smaller than a typical MAN.

This term is most often used to discuss the implementation of networks for a contiguous area. For Ethernet based networks in the past, when layer 2 switching (i.e., bridging (networking) was cheaper than routing, campuses were good candidates for layer 2 networks, until they grew to very large size. Today, a campus may use a mixture of routing and bridging. The network elements used, called "campus switches", tend to be optimized to have many Ethernet-family (i.e., IEEE 802.3) interfaces rather than an arbitrary mixture of Ethernet and WAN interfaces.

[edit] Metropolitan Area Network (MAN)

Main article: Metropolitan Area Network

A Metropolitan Area Network is a network that connects two or more Local Area Networks or Campus Area Networks together but does not extend beyond the boundaries of the immediate town, city, or metropolitan area. Multiple routers, switches & hubs are connected to create a MAN.

[edit] Wide Area Network (WAN)

Main article: Wide Area Network

A WAN is a data communications network that covers a relatively broad geographic area (i.e. one city to another and one country to another country) and that often uses transmission facilities provided by common carriers, such as telephone companies. WAN technologies generally function at the lower three layers of the OSI reference model: the physical layer, the data link layer, and the network layer.

[edit] Global Area Network (GAN)

Main article: Global Area Network

Global area networks (GAN) specifications are in development by several groups, and there is no common definition. In general, however, a GAN is a model for supporting mobile communications across an arbitrary number of wireless LANs, satellite coverage areas, etc. The key challenge in mobile communications is "handing off" the user communications from one local coverage area to the next. In IEEE Project 802, this involves a succession of terrestrial Wireless local area networks (WLAN) ^[3]. INMARSAT has defined a satellite-based Broadband Global Area Network (BGAN).

IEEE mobility efforts focus on the data link layer and make assumptions about the media. Mobile IP is a network layer technique, developed by the IETF, which is independent of the media type and can run over different media while still keeping the connection.

[edit] Internetwork

Main article: Internetwork

Two or more networks or network segments connected using devices that operate at layer 3 (the 'network' layer) of the OSI Basic Reference Model, such as a router. Any interconnection among or between public, private, commercial, industrial, or governmental networks may also be defined as an internetwork.

In modern practice, the interconnected networks use the Internet Protocol. There are at least three variants of internetwork, depending on who administers and who participates in them:

Intranet
Extranet
"The" Internet

Intranets and extranets may or may not have connections to the Internet. If connected to the Internet, the intranet or extranet is normally protected from being accessed from the Internet without proper authorization. The Internet itself is not considered to be a part of the intranet or extranet, although the Internet may serve as a portal for access to portions of an extranet.

[edit] Intranet

Main article: Intranet

An intranet is a set of interconnected networks, using the Internet Protocol and uses IP-based tools such as web browsers, that is under the control of a single administrative entity. That administrative entity closes the intranet to the rest of the world, and allows only specific users. Most commonly, an intranet is the internal network of a company or other enterprise.

[edit] Extranet

Main article: Extranet

An extranet is a network or internetwork that is limited in scope to a single organization or entity but which also has limited connections to the networks of one or more other usually, but not necessarily, trusted organizations or entities (e.g. a company's customers may be given access to some part of its intranet creating in this way an extranet, while at the same time the customers may not be considered 'trusted' from a security standpoint). Technically, an extranet may also be categorized as a CAN, MAN, WAN, or other type of network, although, by definition, an extranet cannot consist of a single LAN; it must have at least one connection with an external network.

[edit] Internet

Main article: Internet

A specific internetwork , consisting of a worldwide interconnection of governmental, academic, public, and private networks based upon the Advanced Research Projects Agency Network (ARPANET) developed by ARPA of the U.S. Department of Defense – also home to the World Wide Web (WWW) and referred to as the 'Internet' with a capital 'I' to distinguish it from other generic internetworks.

Participants in the Internet, or their service providers, use IP Addresses obtained from address registries that control assignments. Service providers and large enterprises also exchange information on the reachability of their address ranges through the BGP Border Gateway Protocol.

[edit] Basic Hardware Components

All networks are made up of basic hardware building blocks to interconnect network nodes, such as Network Interface Cards (NICs), Bridges, Hubs, Switches, and Routers. In addition, some method of connecting these building blocks is required, usually in the form of galvanic cable (most commonly Category 5 cable). Less common are microwave links (as in IEEE 802.11) or optical cable ("optical fiber").

[edit] Network Interface Cards

Main article: Network card

A network card, network adapter or NIC (network interface card) is a piece of computer hardware designed to allow computers to communicate over a computer network. It provides physical access to a networking medium and often provides a low-level addressing system through the use of MAC addresses. It allows users to connect to each other either by using cables or wirelessly.

[edit] Repeaters

Main article: Repeater

A repeater is an electronic device that receives a signal and retransmits it at a higher level or higher power, or onto the other side of an obstruction, so that the signal can cover longer distances without degradation.

Because repeaters work with the actual physical signal, and do not attempt to interpret the data being transmitted, they operate on the Physical layer, the first layer of the OSI model.

[edit] Hubs

Main article: Network hub

A hub contains multiple ports. When a packet arrives at one port, it is copied to all the ports of the hub. When the packets are copied, the destination address in the frame does not change to a broadcast address. It does this in a rudimentary way, it simply copies the data to all of the Nodes connected to the hub. ^[4]

[edit] Bridges

Main article: Network bridge

A network bridge connects multiple network segments at the data link layer (layer 2) of the OSI model. Bridges do not promiscuously copy traffic to all ports, as hubs do. but learns which MAC addresses are reachable through specific ports. Once the bridge associates a port and an address, it will send traffic for that address only to that port. Bridges do send broadcasts to all ports except the one on which the broadcast was received.

Bridges learn the association of ports and addresses by examining the source address of frames that it sees on various ports. Once a frame arrives through a port, its source address is stored and the bridge assumes that MAC address is associated with that port. The first time that a previously unknown destination address is seen, the bridge will forward the frame to all ports other than the one on which the frame arrived.

Bridges come in three basic types:

Local bridges: Directly connect local area networks (LANs)
Remote bridges: Can be used to create a wide area network (WAN) link between LANs. Remote bridges, where the connecting link is slower than the end networks, largely have been replaced by routers.
Wireless bridges: Can be used to join LANs or connect remote stations to LANs.

[edit] Switches

Main article: Network switch

Switches are a marketing term that encompasses routers and bridges, as well as devices that may distribute traffic on load or by application content (e.g., a Web URL identifier). Switches may operate at one or more OSI layers, including physical, data link, network, or transport (i.e., end-to-end). A device that operates simultaneously at more than one of these layers is called a multilayer switch.

Overemphasizing the ill-defined term "switch" often leads to confusion when first trying to understand networking. Many experienced network designers and operators recommend starting with the logic of devices dealing with only one protocol level, not all of which are covered by OSI. Multilayer device selection is an advanced topic that may lead to selecting particular implementations, but multilayer switching is simply not a real-world design concept.

[edit] Routers

Main article: Router

Routers are the networking device that forward data packets along networks by using headers and forwarding tables to determine the best path to forward the packets. Routers work at the network layer of the TCP/IP model or layer 3 of the OSI model. Routers also provide interconnectivity between like and unlike media (RFC 1812) This is accomplished by examining the Header of a data packet, and making a decision on the next hop to which it should be sent (RFC 1812) They use preconfigured static routes, status of their hardware interfaces, and routing protocols to select the best route between any two subnets. A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISP's network. Some DSL and cable modems, for home use, have been integrated with routers to allow multiple home computers to access the Internet.

[edit] Building a simple computer network

A simple computer network may be constructed from two computers by adding a network adapter (Network Interface Controller (NIC)) to each computer and then connecting them together with a special cable called a crossover cable. This type of network is useful for transferring information between two computers that are not normally connected to each other by a permanent network connection or for basic home networking applications. Alternatively, a network between two computers can be established without dedicated extra hardware by using a standard connection such as the RS-232 serial port on both computers, connecting them to each other via a special crosslinked null modem cable.

Practical networks generally consist of more than two interconnected computers and generally require special devices in addition to the Network Interface Controller that each computer needs to be equipped with. Examples of some of these special devices are hubs, switches and routers.

[edit] Ancillary equipment used by networks

To keep a network operating, to diagnose failures or degradation, and to circumvent problems, networks may have a wide-ranging amount of ancillary equipment.

[edit] Providing Electrical Power

Individual network components may have surge protectors - an appliance designed to protect electrical devices from voltage spikes. Surge protectors attempt to regulate the voltage supplied to an electric device by either blocking or shorting to ground voltage above a safe threshold.^[5]

Beyond the surge protector, network elements may have uninterruptible power supplies (UPS), which can be anywhere from a line-charged battery to take the element through a brief power dropout, to an extensive network of generators and large battery banks that can protect the network for hours or days of commercial power outages.

A network as simple as two computers linked with a crossover cable has several points at which the network could fail: either network interface, and the cable. Large networks, without careful design, can have many points at which a single failure could disable the network.

When networks are critical the general rule is that they should have no single point of failure. The broad factors that can bring down networks, according to the Software Engineering Institute ^[6] at Carnegie-Mellon University:

Attacks: these include software attacks by various miscreants (e.g., malicious hackers, computer criminals) as well as physical destruction of facilities.
Failures: these are in no way deliberate, but range from human error in entering commands, bugs in network element executable code, failures of electronic components, and other things that involve deliberate human action or system design.
Accidents: Ranging from spilling coffee into a network element to a natural disaster or war that destroys a data center, these are largely unpredictable events. Survivability from severe accidents will require physically diverse, redundant facilities. Among the extreme protections against both accidents and attacks are airborne command posts and communications relays^[7], which either are continuously in the air, or take off on warning. In like manner, systems of communications satellites may have standby spares in space, which can be activated and brought into the constellation.

[edit] Dealing with Power Failures

One obvious form of failure is the loss of electrical power. Depending on the criticality and budget of the network, protection from power failures can range from simple filters against excessive voltage spikes, to consumer-grade Uninterruptible Power Supplies(UPS) that can protect against loss of commercial power for a few minutes, to independent generators with large battery banks. Critical installations may switch from commercial to internal power in the event of a brownout,where the voltage level is below the normal minimum level specified for the system. Systems supplied with three-phase electric power also suffer brownouts if one or more phases are absent, at reduced voltage, or incorrectly phased. Such malfunctions are particularly damaging to electric motors. Some brownouts, called voltage reductions, are made intentionally to prevent a full power outage.

Some network elements operate in a manner to protect themselves and shut down gracefully in the event of a loss of power. These might include noncritical application and network management servers, but not true network elements such as routers. UPS may provide a signal called the "Power-Good" signal. Its purpose is to tell the computer all is well with the power supply and that the computer can continue to operate normally. If the Power-Good signal is not present, the computer shuts down. The Power-Good signal prevents the computer from attempting to operate on improper voltages and damaging itself

To help standardize approaches to power failures, the Advanced Configuration and Power Interface (ACPI) specification is an open industry standard first released in December 1996 developed by HP, Intel, Microsoft, Phoenix and Toshiba that defines common interfaces for hardware recognition, motherboard and device configuration and power management.

[edit] Monitoring and Diagnostic Equipment

Networks, depending on their criticality and the skill set available among the operators, may have a variety of temporarily or permanently connected performance measurement and diagnostic equipment. Routers and bridges intended more for the enterprise or ISP market than home use, for example, usually record the amount of traffic and errors experienced on their interfaces.

Diagnostic equipment, to isolate failures, may be nothing more complicated than a spare piece of equipment. If the problem disappears when the spare is manually replaced, the problem has been diagnosed. More sophisticated and expensive installations will have spare elements that can automatically replace a failed unit. Failures can be made transparent to user computers with techniques such as the Virtual Router Redundancy Protocol (VRRP), as specified in RFC 3768

Internet Amazon

2008-01-29T16:05:00.000+07:00

That old phone cord is tying Verizon down.

Verizon Communications said on Monday that its traditional telephone business remained a drag on the bottom line. But the company said it was not yet seeing the effect of a slowing economy, and its wireless business continued to show promising growth.

Verizon announced net income of $1.07 billion for the fourth quarter, ended Dec. 31, up from $1.03 billion in the period a year earlier, roughly in line with analysts’ estimates. Its operating revenue rose 5.6 percent, to $23.8 billion. For the year, revenue was up 6.1 percent, to $93.4 billion.

The company’s cellular unit, Verizon Wireless, which is a joint venture with Vodafone Group, was the brightest spot, adding two million new customers in the fourth quarter for a total of 65.7 million. The number of home broadband subscribers grew 17.9 percent in 2007 from the previous year.

The traditional telephone business was a different story. Verizon lost 10.6 percent of its residential lines in 2007. Over all, the total number of landlines, including business customers, fell to 41.4 million in 2007 from 45.1 million in 2006, a drop of 8.1 percent.

Craig Moffett, a senior telecommunications analyst at Sanford C. Bernstein & Company, wrote in a report discussing the earnings that Verizon’s traditional business is showing “more than a little strain.” He added: “If a principal appeal of Verizon’s shares is their presumed resilience in the face of economic weakness, their results must be judged as mixed. Wireless is a clear positive, but weakness in the consumer wireline business cannot be easily dismissed.”

Continued growth in the wireless business, of course, is the result of a continuing shift in consumer behavior as people turn to mobile phones not only to talk to friends and family, but also to listen to music, send text messages and use the Internet.

Dennis F. Strigl, Verizon’s president and chief operating officer, stressed in an interview that Verizon did not plan to lower its sales projections for this month because of the slowing economy, something other communications companies have done in recent weeks. He declined to give a forecast for future months.

Instead, he said, the biggest challenge for companies like Verizon is competition from cable companies and newer entrants. “I think the impact of the economy on the business is much less likely than competition,” said Mr. Strigl.

To retain more residential customers, Verizon is betting on its FiOS fiber-optic network, which allows the company to offer television, phone and Internet services in a bundled package. The company has more than a million FiOS TV customers, Mr. Strigl said. Over time, he said, Verizon expects to shift more spending from its core business to FiOS.

When asked if traditional landline service would ever go away, Mr. Strigl said that its definition would be expanded to include video and data as well as voice. “I think we are rapidly transforming into something other than a utility,” he said.

Verizon’s stock rose 0.9 percent to close at $38.11 a share after the earnings report.

Games Internet

2008-01-29T16:00:00.000+07:00

GREAT NECK, N.Y. — The games had begun. In a darkened classroom at Great Neck South High School on a recent afternoon, the Advanced Placement physics students sped through a pop quiz, furiously pressing keys on hand-held clickers. A projection screen tracked their responses in real time, showing who knew what through an animated display of spaceships — individually numbered for each student — that blasted off or fell by the wayside with each right or wrong answer.

Skip to next paragraph

Joyce Dopkeen/The New York Times

As students in Matt Sckalor’s physics class at Great Neck South High School click their answers, the results go up on a screen. They can instantly see their progress, and how the class did.

The students were not competing for grades (it was only a practice quiz), but they certainly acted as if they were.

“Let’s go, let’s go!” yelled a boy from the back of the class. “What’s the next question?” The Great Neck district has been introducing the clickers in an effort to liven up traditional classroom teaching with a more interactive approach. After a successful test at one of its high schools, Great Neck expanded the technology to other schools.

The clickers are part of an increasingly popular technology known as an audience response system, which has been used for everything from surveying game show audiences to polling registered voters. That technology is now spreading to public and private schools across the country.

The Los Angeles school district has spent about $503,000 to buy clickers for more than two dozen middle schools since 2005, district officials said. Smaller districts in the Dallas and Atlanta suburbs have also invested in them, according to school officials and companies that manufacture the devices. In New York City, a dozen schools across the five boroughs have experimented with the devices. And in St. Paul, the clickers are routinely used to train teachers and administrators and to get reaction from parents at community meetings.

In a typical system, the clickers record data from individuals, and transmit that information, through wireless technology, to a computer program. The program can instantly display the results, tally them and present them in elaborate spreadsheets and eye-catching graphics like spaceships or “Jeopardy!”-style boards. It can track the percentage of correct answers received for each question as well as the participation rate among all users.

The growth of the clicker technology in schools has been “very big and fast paced,” said Jaci Hendricks, a spokeswoman for Qwizdom, one of several companies that manufacture the clickers. In the last five years alone, Qwizdom has supplied more than 750,000 clickers to schools nationwide, including those in Great Neck, New York City and Los Angeles.

In Great Neck, the district spent $18,000 to buy the clickers after its technology director, Marc Epstein, saw them at education conferences. He thought they presented an advance over earlier classroom technology, which he said had focused on providing hardware to students (desktop computers, laptops and printers, for example), or helping teachers deliver lessons (“smart boards” and projectors).

In contrast, he said, the clickers used technology to assess student learning.

Mr. Epstein found an ally in Randolph Ross, the principal of Great Neck South, who agreed to have the clickers tested at his school, which has 1,300 students, in 2006. Mr. Ross, who constructs crossword puzzles for a hobby, said that some teachers and students had already been requesting an electronic buzzer system to use for classroom “Jeopardy!” games and quiz bowls.

“I’m a big games person,” Mr. Ross said. “I’m very supportive of all these trivia contests because it’s good mental gymnastics and it’s fun.”

Mr. Ross had just the teacher to try out the new technology: Matt Sckalor, the Advanced Placement physics teacher, who had appeared as a contestant on “Who Wants to Be a Millionaire” in February 2000. (He did not win any money.)

Mr. Sckalor said that he was sold on the clickers because he could check on the progress of every student, not just the ones who frequently raised their hands and tended to dominate the discussions.

Freed From the Page, but a Book Nonetheless

2008-01-29T15:57:00.000+07:00

PRINTED books provide pleasures no device created by an electrical engineer can match. The sweet smell of a brand-new book. The tactile pleasures of turning a page. The reassuring sight on one’s bookshelves of personal journeys.

Skip to next paragraph

Amazon.com

The Amazon Kindle uses E Ink technology to display images in four shades of gray.

But not one of these explains why books have resisted digitization. That’s simpler: Books are portable and easy to read.

Building a portable electronic reader was the easy part; matching the visual quality of ink on paper took longer. But display technology has advanced to the point where the digital page is easy on the eyes, too. At last, an e-reader performs well when placed in page-to-page competition with paper.

As a result, the digitization of personal book collections is certain to have its day soon.

Music shows the way. The digitization of personal music collections began, however, only after the right combination of software and hardware — iTunes Music Store and the iPod — arrived. And as Apple did for music lovers, some company will devise an irresistible combination of software and hardware for book buyers. That company may be Amazon.

Amazon’s first iteration of an electronic book reader is the Kindle. Introduced in November, it weighs about 10 ounces, holds more than 200 full-length books and can display newspapers, magazines and blogs. It uses E Ink technology, developed by the company of that name, that produces sharply defined text yet draws power only when a page is changed, not as it is displayed.

Sony uses E Ink in its e-book Reader, which it introduced in 2006, but the Kindle has a feature that neither Sony nor many e-reader predecessors ever possessed: books and other content can be loaded wirelessly, from just about anywhere in the United States, using the high-speed EVDO network from Sprint.

This may turn out to be a red-letter day in the history of convenience — our age’s equivalent of that magical moment FedEx introduced next-day delivery and people asked, “How was life possible before this?”

The Kindle is expensive — $399 — but it sold out in just six hours after its debut on Nov. 19. Since then, supplies have consistently lagged behind demand, and a waiting list remains in place.

The Kindle gets many things right, or at least I assume it does. I haven’t had much of a chance to test out my demonstration unit. My wife, skeptical that a digital screen could ever approach the readability of ink on paper, was so intrigued by the Kindle when it arrived last week that she snatched it from my grasp. I haven’t been able to pry it away from her since.

I can see that the text looks splendid. But when one presses a bar to “turn” a page, the image reverses in a way I found jarring: the light background turns black and the black text turns white, then the new page appears and everything returns to normal. My wife said she wasn’t bothered by this at all, and I didn’t have enough of a chance to see if I would soon get used to it.

Steven P. Jobs, the chief executive of Apple, has nothing to fear from the Kindle. No one would regard it as competition for the iPod. It displays text in four exciting shades of gray, and does that one thing very well. It can do a few other things: for instance, it has a headphone jack and can play MP3 files, but it is not well suited for navigating a large collection of music tracks.

Yet, when Mr. Jobs was asked two weeks ago at the Macworld Expo what he thought of the Kindle, he heaped scorn on the book industry. “It doesn’t matter how good or bad the product is; the fact is that people don’t read anymore,” he said. “Forty percent of the people in the U.S. read one book or less last year.”

To Mr. Jobs, this statistic dooms everyone in the book business to inevitable failure.

Only the business is not as ghostly as he suggests. In 2008, book publishing will bring in about $15 billion in revenue in the United States, according to the Book Industry Study Group, a trade association.

One can only wonder why, by the Study Group’s estimate, 408 million books will be bought this year if no one reads anymore?

A survey conducted in August 2007 by Ipsos Public Affairs for The Associated Press found that 27 percent of Americans had not read a book in the previous year. Not as bad as Mr. Jobs’s figure, but dismaying to be sure. Happily, however, the same share — 27 percent — read 15 or more books.

In fact, when we exclude Americans who had not read a single book in that year, the average number of books read was 20, raised by the 8 percent who read 51 books or more. In other words, a sizable minority does not read, but the overall distribution is balanced somewhat by those who read a lot.

If a piece of the book industry’s $15 billion seems too paltry for Mr. Jobs to bother with, he is forgetting that Apple reached its current size only recently. Last week, Apple reported that it posted revenue of $9.6 billion in the quarter that spanned October to December 2007, its best quarter ever, after $24 billion in revenue in the 2007 fiscal year, which ended in September.

But as recently as 2001, before the iPhone and the iPod, Apple was a niche computer company without a mass market hit. It was badly hurt by the 2001 recession and reported revenue of only $5.3 billion for the year. This is, by coincidence, almost exactly what Barnes & Noble reported in revenue for its 2007 fiscal year. In neither case did the company owners look at that number, decide to chain the doors permanently shut and call it quits.

Amazon does not release details about revenue for books, but books were its first business. And Andrew Herdener, a company spokesman, said that Amazon’s book sales “have increased every year since the company began.”

The book world has always had an invisible asset that makes up for what it lacks in outsize revenue and profits: the passionate attachment that its authors, editors and most frequent customers have to books themselves. Indeed, in this respect, avid book readers resemble avid Mac users.

The object we are accustomed to calling a book is undergoing a profound modification as it is stripped of its physical shell. Kindle’s long-term success is still unknown, but Amazon should be credited with imaginatively redefining its original product line, replacing the book business with the reading business.

Randall Stross is an author based in Silicon Valley and a professor of business at San Jose State University. E-mail: stross@nytimes.com.

Security Web

2008-01-29T15:25:00.002+07:00

Security4Web offers a broad range of information on credit card fraud, identity theft, data mining components, viruses, trojans, backdoor viruses, spam prevention and protection, security related articles, surveys and reports from reputable sources, tips, fraud schemes, do's and don't's, and last but not least links to law enforcement authorities to whom people may address to if they become victims.

Security4Web addresses itself both to those experienced with the Internet and to those still experiencing it. From our point of view it doesn't really matter how much experience people gain browsing the Internet when it comes to online threats.
In a world flooded with information it is difficult to sort out the solution that fits you best. This is where Security4Web comes into picture, and this is what sets us apart from other websites: we provide the proper information and in the same time a wide range of tools to serve individuals' needs, to keep them secure from the dark side of the Internet. Our success recipe is: accurate information backed up with suitable tools to help Internet users detect, prevent, and protect themselves from online threats. All "ingredients" in the same place.

In our attempt to keep people informed we center upon a large area of threats that can be experienced online: malware, identity theft, charge backs, and upon the subjects that can be affected: PC users, email users, merchants, business managers, parents and children. In other words, we rely upon three main co-ordinates: online threats, consequences and solutions.
Now it is up to you to keep cyber threats away.

Internet security

2008-01-29T15:25:00.001+07:00

In the computer industry, Internet security refers to techniques for ensuring that data stored in a computer cannot be read or compromised by any individuals without authorization. Most security measures involve data encryption and passwords. Data encryption is the translation of data into a form that is unintelligible without a deciphering mechanism. A password is a secret word or phrase that gives a user access to a particular program or system.

Internet security professionals should be fluent in the four major aspects:

Penetration testing
Intrusion Detection
Incidence Response
Legal / Audit Compliance

[hide]

[edit] Routers

For more details on this topic, see Router.

Network Address Translation (NAT) typically has the effect of preventing connections from being established inbound into a computer, whilst permitting connections out. For a small home network, software NAT can be used on the computer with the Internet connection, providing similar behaviour to a router and similar levels of security, but for a lower cost and lower complexity.

[edit] Firewalls

For more details on this topic, see Firewall.

A firewall blocks all "roads and cars" through authorized ports on your computer, thus restricting unfettered access. A stateful firewall is a more secure form of firewall, and system administrators often combine a proxy firewall with a packet-filtering firewall to create a highly secure system. Most home users use a software firewall. These types of firewalls can create a log file where it records all the connection details (including connection attempts) with the PC.

[edit] Anti-virus

For more details on this topic, see Malware.

Some people or companies with malicious intentions write programs like computer viruses, worms, trojan horses and spyware. These programs are all characterised as being unwanted software that install themselves on your computer through deception.

Trojan horses are simply programs that conceal their true purpose or include a hidden functionality that a user would not want.

Worms are characterised by having the ability to replicate themselves and viruses are similar except that they achieve this by adding their code onto third party software. Once a virus or worm has infected a computer, it would typically infect other programs (in the case of viruses) and other computers.

Viruses also slow down system performance and cause strange system behavior and in many cases do serious harm to computers, either as deliberate, malicious damage or as unintentional side effects.

In order to prevent damage by viruses and worms, users typically install antivirus software, which runs in the background on the computer, detecting any suspicious software and preventing it from running.

Some malware that can be classified as trojans with a limited payload are not detected by most antivirus software and may require the use of other software designed to detect other classes of malware, including spyware.

[edit] Anti-spyware

For more details on this topic, see Malware.

There are several kinds of threats:

Spyware is software that runs on a computer without the explicit permission of its user. It often gathers private information from a users computer and sends this data over the Internet back to the software manufacturer.
Adware is software that runs on a computer without the owner's consent, much like spyware. However, instead of taking information, it typically runs in the background and displays random or targeted pop-up advertisements. In many cases, this slows the computer down and may also cause software conflicts.

[edit] Browser choice

Internet Explorer is currently the most widely used web browser in the world,^[1] making it the prime target for phishing and many other possible attacks.

[edit] See also

[edit] External links

What are keystroke loggers? - detailed advice and information on keystroke loggers, and trojan horses, and how to remove them
Security4web - detailed advice and information on Internet security for individuals and families
Wireless Safety - Up to date info on the latest security threats, top news stories, and step by step tutorials on how to best protect yourself and family or organization.
SecurityBay - security news, articles and vulnerability database for security-aware Internet users
Broadband Reports - FAQs and forums on internet security etc
PasswordMaker and PwdHash are Firefox & IE browser extensions that transparently converts a user's password into a domain-specific password.
FoxyProxy
Free website reputation ranking software by Against Intuition Inc.
Internet security by JC & Goio (security programs).

Computer

2008-01-29T15:02:00.000+07:00

This article is about the machine. For the magazine, see Computer (magazine). For the profession, see human computer.

Look up computer in
Wiktionary, the free dictionary.

The NASA Columbia Supercomputer.

A computer in a wristwatch.

A computer is a machine that manipulates data according to a list of instructions.

Computers take numerous physical forms. The first devices that resemble modern computers date to the mid-20th century (around 1940 - 1945), although the computer concept and various machines similar to computers existed earlier. Early electronic computers were the size of a large room, consuming as much power as several hundred modern personal computers.^[1] Modern computers are based on comparatively tiny integrated circuits and are millions to billions of times more capable while occupying a fraction of the space.^[2] Today, simple computers may be made small enough to fit into a wristwatch and be powered from a watch battery. Personal computers in various forms are icons of the Information Age and are what most people think of as "a computer"; however, the most common form of computer in use today is the embedded computer. Embedded computers are small, simple devices that are used to control other devices — for example, they may be found in machines ranging from fighter aircraft to industrial robots, digital cameras, and children's toys.

The ability to store and execute lists of instructions called programs makes computers extremely versatile and distinguishes them from calculators. The Church–Turing thesis is a mathematical statement of this versatility: any computer with a certain minimum capability is, in principle, capable of performing the same tasks that any other computer can perform. Therefore, computers with capability and complexity ranging from that of a personal digital assistant to a supercomputer are all able to perform the same computational tasks given enough time and storage capacity.

History of computing

Main article: History of computer hardware

The Jacquard loom was one of the first programmable devices.

It is difficult to identify any one device as the earliest computer, partly because the term "computer" has been subject to varying interpretations over time. Originally, the term "computer" referred to a person who performed numerical calculations (a human computer), often with the aid of a mechanical calculating device.

The history of the modern computer begins with two separate technologies - that of automated calculation and that of programmability.

Examples of early mechanical calculating devices included the abacus, the slide rule and arguably the astrolabe and the Antikythera mechanism (which dates from about 150-100 BC). The end of the Middle Ages saw a re-invigoration of European mathematics and engineering, and Wilhelm Schickard's 1623 device was the first of a number of mechanical calculators constructed by European engineers. However, none of those devices fit the modern definition of a computer because they could not be programmed.

Hero of Alexandria (c. 10 – 70 AD) built a mechanical theater which performed a play lasting 10 minutes and was operated by a complex system of ropes and drums that might be considered to be a means of deciding which parts of the mechanism performed which actions - and when.^[3] This is the essence of programmability. In 1801, Joseph Marie Jacquard made an improvement to the textile loom that used a series of punched paper cards as a template to allow his loom to weave intricate patterns automatically. The resulting Jacquard loom was an important step in the development of computers because the use of punched cards to define woven patterns can be viewed as an early, albeit limited, form of programmability.

It was the fusion of automatic calculation with programmability that produced the first recognisable computers. In 1837, Charles Babbage was the first to conceptualize and design a fully programmable mechanical computer that he called "The Analytical Engine".^[4] Due to limited finances, and an inability to resist tinkering with the design, Babbage never actually built his Analytical Engine.

Large-scale automated data processing of punched cards was performed for the U.S. Census in 1890 by tabulating machines designed by Herman Hollerith and manufactured by the Computing Tabulating Recording Corporation, which later became IBM. By the end of the 19th century a number of technologies that would later prove useful in the realization of practical computers had begun to appear: the punched card, Boolean algebra, the vacuum tube (thermionic valve) and the teleprinter.

During the first half of the 20th century, many scientific computing needs were met by increasingly sophisticated analog computers, which used a direct mechanical or electrical model of the problem as a basis for computation. However, these were not programmable and generally lacked the versatility and accuracy of modern digital computers.

*Defining characteristics of five early digital computers*
Computer	First operation	Place	Decimal/Binary	Electronic	Programmable	Turing complete
Zuse Z3	May 1941	Germany	binary	No	By punched film stock	Yes (1998)
Atanasoff–Berry Computer	Summer 1941	USA	binary	Yes	No	No
Colossus	December 1943 / January 1944	UK	binary	Yes	Partially, by rewiring	No
Harvard Mark I – IBM ASCC	1944	USA	decimal	No	By punched paper tape	Yes (1998)
ENIAC	1944	USA	decimal	Yes	Partially, by rewiring	Yes
ENIAC	1948	USA	decimal	Yes	By Function Table ROM	Yes

A succession of steadily more powerful and flexible computing devices were constructed in the 1930s and 1940s, gradually adding the key features that are seen in modern computers. The use of digital electronics (largely invented by Claude Shannon in 1937) and more flexible programmability were vitally important steps, but defining one point along this road as "the first digital electronic computer" is difficult (Shannon 1940). Notable achievements include:

EDSAC was one of the first computers to implement the stored program (von Neumann) architecture.

Konrad Zuse's electromechanical "Z machines". The Z3 (1941) was the first working machine featuring binary arithmetic, including floating point arithmetic and a measure of programmability. In 1998 the Z3 was proved to be Turing complete, therefore being the world's first operational computer.
The non-programmable Atanasoff–Berry Computer (1941) which used vacuum tube based computation, binary numbers, and regenerative capacitor memory.
The secret British Colossus computer (1944), which had limited programmability but demonstrated that a device using thousands of tubes could be reasonably reliable and electronically reprogrammable. It was used for breaking German wartime codes.
The Harvard Mark I (1944), a large-scale electromechanical computer with limited programmability.
The U.S. Army's Ballistics Research Laboratory ENIAC (1946), which used decimal arithmetic and is sometimes called the first general purpose electronic computer (since Konrad Zuse's Z3 of 1941 used electromagnets instead of electronics). Initially, however, ENIAC had an inflexible architecture which essentially required rewiring to change its programming.

Several developers of ENIAC, recognizing its flaws, came up with a far more flexible and elegant design, which came to be known as the stored program architecture or von Neumann architecture. This design was first formally described by John von Neumann in the paper "First Draft of a Report on the EDVAC", published in 1945. A number of projects to develop computers based on the stored program architecture commenced around this time, the first of these being completed in Great Britain. The first to be demonstrated working was the Manchester Small-Scale Experimental Machine (SSEM) or "Baby". However, the EDSAC, completed a year after SSEM, was perhaps the first practical implementation of the stored program design. Shortly thereafter, the machine originally described by von Neumann's paper—EDVAC—was completed but did not see full-time use for an additional two years.

Nearly all modern computers implement some form of the stored program architecture, making it the single trait by which the word "computer" is now defined. By this standard, many earlier devices would no longer be called computers by today's definition, but are usually referred to as such in their historical context. While the technologies used in computers have changed dramatically since the first electronic, general-purpose computers of the 1940s, most still use the von Neumann architecture. The design made the universal computer a practical reality.

Microprocessors are miniaturized devices that often implement stored program CPUs.

Vacuum tube-based computers were in use throughout the 1950s, but were largely replaced in the 1960s by transistor-based devices, which were smaller, faster, cheaper, used less power and were more reliable. These factors allowed computers to be produced on an unprecedented commercial scale. By the 1970s, the adoption of integrated circuit technology and the subsequent creation of microprocessors such as the Intel 4004 caused another leap in size, speed, cost and reliability. By the 1980s, computers had become sufficiently small and cheap to replace simple mechanical controls in domestic appliances such as washing machines. Around the same time, computers became widely accessible for personal use by individuals in the form of home computers and the now ubiquitous personal computer. In conjunction with the widespread growth of the Internet since the 1990s, personal computers are becoming as common as the television and the telephone and almost all modern electronic devices contain a computer of some kind.

Stored program architecture

Main articles: Computer program and Computer programming

The defining feature of modern computers which distinguishes them from all other machines is that they can be programmed. That is to say that a list of instructions (the program) can be given to the computer and it will store them and carry them out at some time in the future.

In most cases, computer instructions are simple: add one number to another, move some data from one location to another, send a message to some external device, etc. These instructions are read from the computer's memory and are generally carried out (executed) in the order they were given. However, there are usually specialized instructions to tell the computer to jump ahead or backwards to some other place in the program and to carry on executing from there. These are called "jump" instructions (or branches). Furthermore, jump instructions may be made to happen conditionally so that different sequences of instructions may be used depending on the result of some previous calculation or some external event. Many computers directly support subroutines by providing a type of jump that "remembers" the location it jumped from and another instruction to return to the instruction following that jump instruction.

Program execution might be likened to reading a book. While a person will normally read each word and line in sequence, they may at times jump back to an earlier place in the text or skip sections that are not of interest. Similarly, a computer may sometimes go back and repeat the instructions in some section of the program over and over again until some internal condition is met. This is called the flow of control within the program and it is what allows the computer to perform tasks repeatedly without human intervention.

Comparatively, a person using a pocket calculator can perform a basic arithmetic operation such as adding two numbers with just a few button presses. But to add together all of the numbers from 1 to 1,000 would take thousands of button presses and a lot of time—with a near certainty of making a mistake. On the other hand, a computer may be programmed to do this with just a few simple instructions. For example:

        mov      #0,sum     ; set sum to 0
       mov      #1,num     ; set num to 1
loop:   add      num,sum    ; add num to sum
       add      #1,num     ; add 1 to num
       cmp      num,#1000  ; compare num to 1000
       ble      loop       ; if num <= 1000, go back to 'loop'
       halt                ; end of program. stop running

Once told to run this program, the computer will perform the repetitive addition task without further human intervention. It will almost never make a mistake and a modern PC can complete the task in about a millionth of a second.^[5]

However, computers cannot "think" for themselves in the sense that they only solve problems in exactly the way they are programmed to. An intelligent human faced with the above addition task might soon realize that instead of actually adding up all the numbers one can simply use the equation

and arrive at the correct answer (500,500) with little work.^[6] In other words, a computer programmed to add up the numbers one by one as in the example above would do exactly that without regard to efficiency or alternative solutions.

Programs

A 1970s punched card containing one line from a FORTRAN program. The card reads: "Z(1) = Y + W(1)" and is labelled "PROJ039" for identification purposes.

In practical terms, a computer program might include anywhere from a dozen instructions to many millions of instructions for something like a word processor or a web browser. A typical modern computer can execute billions of instructions every second and nearly never make a mistake over years of operation.

Large computer programs may take teams of computer programmers years to write and the probability of the entire program having been written completely in the manner intended is unlikely. Errors in computer programs are called bugs. Sometimes bugs are benign and do not affect the usefulness of the program, in other cases they might cause the program to completely fail (crash), in yet other cases there may be subtle problems. Sometimes otherwise benign bugs may be used for malicious intent, creating a security exploit. Bugs are usually not the fault of the computer. Since computers merely execute the instructions they are given, bugs are nearly always the result of programmer error or an oversight made in the program's design.^[7]

In most computers, individual instructions are stored as machine code with each instruction being given a unique number (its operation code or opcode for short). The command to add two numbers together would have one opcode, the command to multiply them would have a different opcode and so on. The simplest computers are able to perform any of a handful of different instructions, the more complex computers have several hundred to choose from—each with a unique numerical code. Since the computer's memory is able to store numbers, it can also store the instruction codes. This leads to the important fact that entire programs (which are just lists of instructions) can be represented as lists of numbers and can themselves be manipulated inside the computer just as if they were numeric data. The fundamental concept of storing programs in the computer's memory alongside the data they operate on is the crux of the von Neumann, or stored program, architecture. In some cases, a computer might store some or all of its program in memory that is kept separate from the data it operates on. This is called the Harvard architecture after the Harvard Mark I computer. Modern von Neumann computers display some traits of the Harvard architecture in their designs, such as in CPU caches.

While it is possible to write computer programs as long lists of numbers (machine language) and this technique was used with many early computers,^[8] it is extremely tedious to do so in practice, especially for complicated programs. Instead, each basic instruction can be given a short name that is indicative of its function and easy to remember—a mnemonic such as ADD, SUB, MULT or JUMP. These mnemonics are collectively known as a computer's assembly language. Converting programs written in assembly language into something the computer can actually understand (machine language) is usually done by a computer program called an assembler. Machine languages and the assembly languages that represent them (collectively termed low-level programming languages) tend to be unique to a particular type of computer. For instance, an ARM architecture computer (such as may be found in a PDA or a hand-held videogame) cannot understand the machine language of an Intel Pentium or the AMD Athlon 64 computer that might be in a PC.^[9]

Though considerably easier than in machine language, writing long programs in assembly language is often difficult and error prone. Therefore, most complicated programs are written in more abstract high-level programming languages that are able to express the needs of the computer programmer more conveniently (and thereby help reduce programmer error). High level languages are usually "compiled" into machine language (or sometimes into assembly language and then into machine language) using another computer program called a compiler.^[10] Since high level languages are more abstract than assembly language, it is possible to use different compilers to translate the same high level language program into the machine language of many different types of computer. This is part of the means by which software like video games may be made available for different computer architectures such as personal computers and various video game consoles.

The task of developing large software systems is an immense intellectual effort. It has proven, historically, to be very difficult to produce software with an acceptably high reliability, on a predictable schedule and budget. The academic and professional discipline of software engineering concentrates specifically on this problem.

Example

A traffic light showing red.

Suppose a computer is being employed to drive a traffic light. A simple stored program might say:

Turn off all of the lights
Turn on the red light
Wait for sixty seconds
Turn off the red light
Turn on the green light
Wait for sixty seconds
Turn off the green light
Turn on the yellow light
Wait for two seconds
Turn off the yellow light
Jump to instruction number (2)

With this set of instructions, the computer would cycle the light continually through red, green, yellow and back to red again until told to stop running the program.

However, suppose there is a simple on/off switch connected to the computer that is intended to be used to make the light flash red while some maintenance operation is being performed. The program might then instruct the computer to:

Turn off all of the lights
Turn on the red light
Wait for sixty seconds
Turn off the red light
Turn on the green light
Wait for sixty seconds
Turn off the green light
Turn on the yellow light
Wait for two seconds
Turn off the yellow light
If the maintenance switch is NOT turned on then jump to instruction number 2
Turn on the red light
Wait for one second
Turn off the red light
Wait for one second
Jump to instruction number 11

In this manner, the computer is either running the instructions from number (2) to (11) over and over or its running the instructions from (11) down to (16) over and over, depending on the position of the switch.^[11]

How computers work

Main articles: Central processing unit and Microprocessor

A general purpose computer has four main sections: the arithmetic and logic unit (ALU), the control unit, the memory, and the input and output devices (collectively termed I/O). These parts are interconnected by busses, often made of groups of wires.

The control unit, ALU, registers, and basic I/O (and often other hardware closely linked with these) are collectively known as a central processing unit (CPU). Early CPUs were composed of many separate components but since the mid-1970s CPUs have typically been constructed on a single integrated circuit called a microprocessor.

Control unit

Main articles: CPU design and Control unit

The control unit (often called a control system or central controller) directs the various components of a computer. It reads and interprets (decodes) instructions in the program one by one. The control system decodes each instruction and turns it into a series of control signals that operate the other parts of the computer.^[12] Control systems in advanced computers may change the order of some instructions so as to improve performance.

A key component common to all CPUs is the program counter, a special memory cell (a register) that keeps track of which location in memory the next instruction is to be read from.^[13]

Diagram showing how a particular MIPS architecture instruction would be decoded by the control system.

The control system's function is as follows—note that this is a simplified description, and some of these steps may be performed concurrently or in a different order depending on the type of CPU:

Read the code for the next instruction from the cell indicated by the program counter.
Decode the numerical code for the instruction into a set of commands or signals for each of the other systems.
Increment the program counter so it points to the next instruction.
Read whatever data the instruction requires from cells in memory (or perhaps from an input device). The location of this required data is typically stored within the instruction code.
Provide the necessary data to an ALU or register.
If the instruction requires an ALU or specialized hardware to complete, instruct the hardware to perform the requested operation.
Write the result from the ALU back to a memory location or to a register or perhaps an output device.
Jump back to step (1).

Since the program counter is (conceptually) just another set of memory cells, it can be changed by calculations done in the ALU. Adding 100 to the program counter would cause the next instruction to be read from a place 100 locations further down the program. Instructions that modify the program counter are often known as "jumps" and allow for loops (instructions that are repeated by the computer) and often conditional instruction execution (both examples of control flow).

It is noticeable that the sequence of operations that the control unit goes through to process an instruction is in itself like a short computer program - and indeed, in some more complex CPU designs, there is another yet smaller computer called a microsequencer that runs a microcode program that causes all of these events to happen.

Arithmetic/logic unit (ALU)

Main article: Arithmetic logic unit

The ALU is capable of performing two classes of operations: arithmetic and logic.

The set of arithmetic operations that a particular ALU supports may be limited to adding and subtracting or might include multiplying or dividing, trigonometry functions (sine, cosine, etc) and square roots. Some can only operate on whole numbers (integers) whilst others use floating point to represent real numbers—albeit with limited precision. However, any computer that is capable of performing just the simplest operations can be programmed to break down the more complex operations into simple steps that it can perform. Therefore, any computer can be programmed to perform any arithmetic operation—although it will take more time to do so if its ALU does not directly support the operation. An ALU may also compare numbers and return boolean truth values (true or false) depending on whether one is equal to, greater than or less than the other ("is 64 greater than 65?").

Logic operations involve Boolean logic: AND, OR, XOR and NOT. These can be useful both for creating complicated conditional statements and processing boolean logic.

Superscalar computers contain multiple ALUs so that they can process several instructions at the same time. Graphics processors and computers with SIMD and MIMD features often provide ALUs that can perform arithmetic on vectors and matrices.

Memory

Main article: Computer storage

Magnetic core memory was popular main memory for computers through the 1960s until it was completely replaced by semiconductor memory.

A computer's memory can be viewed as a list of cells into which numbers can be placed or read. Each cell has a numbered "address" and can store a single number. The computer can be instructed to "put the number 123 into the cell numbered 1357" or to "add the number that is in cell 1357 to the number that is in cell 2468 and put the answer into cell 1595". The information stored in memory may represent practically anything. Letters, numbers, even computer instructions can be placed into memory with equal ease. Since the CPU does not differentiate between different types of information, it is up to the software to give significance to what the memory sees as nothing but a series of numbers.

In almost all modern computers, each memory cell is set up to store binary numbers in groups of eight bits (called a byte). Each byte is able to represent 256 different numbers; either from 0 to 255 or -128 to +127. To store larger numbers, several consecutive bytes may be used (typically, two, four or eight). When negative numbers are required, they are usually stored in two's complement notation. Other arrangements are possible, but are usually not seen outside of specialized applications or historical contexts. A computer can store any kind of information in memory as long as it can be somehow represented in numerical form. Modern computers have billions or even trillions of bytes of memory.

The CPU contains a special set of memory cells called registers that can be read and written to much more rapidly than the main memory area. There are typically between two and one hundred registers depending on the type of CPU. Registers are used for the most frequently needed data items to avoid having to access main memory every time data is needed. Since data is constantly being worked on, reducing the need to access main memory (which is often slow compared to the ALU and control units) greatly increases the computer's speed.

Computer main memory comes in two principal varieties: random access memory or RAM and read-only memory or ROM. RAM can be read and written to anytime the CPU commands it, but ROM is pre-loaded with data and software that never changes, so the CPU can only read from it. ROM is typically used to store the computer's initial start-up instructions. In general, the contents of RAM is erased when the power to the computer is turned off while ROM retains its data indefinitely. In a PC, the ROM contains a specialized program called the BIOS that orchestrates loading the computer's operating system from the hard disk drive into RAM whenever the computer is turned on or reset. In embedded computers, which frequently do not have disk drives, all of the software required to perform the task may be stored in ROM. Software that is stored in ROM is often called firmware because it is notionally more like hardware than software. Flash memory blurs the distinction between ROM and RAM by retaining data when turned off but being rewritable like RAM. However, flash memory is typically much slower than conventional ROM and RAM so its use is restricted to applications where high speeds are not required.^[14]

In more sophisticated computers there may be one or more RAM cache memories which are slower than registers but faster than main memory. Generally computers with this sort of cache are designed to move frequently needed data into the cache automatically, often without the need for any intervention on the programmer's part.

Input/output (I/O)

Main article: Input/output

Hard disks are common I/O devices used with computers.

I/O is the means by which a computer receives information from the outside world and sends results back. Devices that provide input or output to the computer are called peripherals. On a typical personal computer, peripherals include input devices like the keyboard and mouse, and output devices such as the display and printer. Hard disk drives, floppy disk drives and optical disc drives serve as both input and output devices. Computer networking is another form of I/O.

Often, I/O devices are complex computers in their own right with their own CPU and memory. A graphics processing unit might contain fifty or more tiny computers that perform the calculations necessary to display 3D graphics^{[citation needed]}. Modern desktop computers contain many smaller computers that assist the main CPU in performing I/O.

Multitasking

Main article: Computer multitasking

While a computer may be viewed as running one gigantic program stored in its main memory, in some systems it is necessary to give the appearance of running several programs simultaneously. This is achieved by having the computer switch rapidly between running each program in turn. One means by which this is done is with a special signal called an interrupt which can periodically cause the computer to stop executing instructions where it was and do something else instead. By remembering where it was executing prior to the interrupt, the computer can return to that task later. If several programs are running "at the same time", then the interrupt generator might be causing several hundred interrupts per second, causing a program switch each time. Since modern computers typically execute instructions several orders of magnitude faster than human perception, it may appear that many programs are running at the same time even though only one is ever executing in any given instant. This method of multitasking is sometimes termed "time-sharing" since each program is allocated a "slice" of time in turn.

Before the era of cheap computers, the principle use for multitasking was to allow many people to share the same computer.

Seemingly, multitasking would cause a computer that is switching between several programs to run more slowly - in direct proportion to the number of programs it is running. However, most programs spend much of their time waiting for slow input/output devices to complete their tasks. If a program is waiting for the user to click on the mouse or press a key on the keyboard, then it will not take a "time slice" until the event it is waiting for has occurred. This frees up time for other programs to execute so that many programs may be run at the same time without unacceptable speed loss.

Multiprocessing

Main article: Multiprocessing

Cray designed many supercomputers that used multiprocessing heavily.

Some computers may divide their work between one or more separate CPUs, creating a multiprocessing configuration. Traditionally, this technique was utilized only in large and powerful computers such as supercomputers, mainframe computers and servers. However, multiprocessor and multi-core (multiple CPUs on a single integrated circuit) personal and laptop computers have become widely available and are beginning to see increased usage in lower-end markets as a result.

Supercomputers in particular often have highly unique architectures that differ significantly from the basic stored-program architecture and from general purpose computers.^[15] They often feature thousands of CPUs, customized high-speed interconnects, and specialized computing hardware. Such designs tend to be useful only for specialized tasks due to the large scale of program organization required to successfully utilize most of a the available resources at once. Supercomputers usually see usage in large-scale simulation, graphics rendering, and cryptography applications, as well as with other so-called "embarrassingly parallel" tasks.

Networking and the Internet

Main articles: Computer networking and Internet

Visualization of a portion of the routes on the Internet.

Computers have been used to coordinate information in multiple locations since the 1950s. The U.S. military's SAGE system was the first large-scale example of such a system, which led to a number of special-purpose commercial systems like Sabre.

In the 1970s, computer engineers at research institutions throughout the United States began to link their computers together using telecommunications technology. This effort was funded by ARPA (now DARPA), and the computer network that it produced was called the ARPANET. The technologies that made the Arpanet possible spread and evolved. In time, the network spread beyond academic and military institutions and became known as the Internet. The emergence of networking involved a redefinition of the nature and boundaries of the computer. Computer operating systems and applications were modified to include the ability to define and access the resources of other computers on the network, such as peripheral devices, stored information, and the like, as extensions of the resources of an individual computer. Initially these facilities were available primarily to people working in high-tech environments, but in the 1990s the spread of applications like e-mail and the World Wide Web, combined with the development of cheap, fast networking technologies like Ethernet and ADSL saw computer networking become almost ubiquitous. In fact, the number of computers that are networked is growing phenomenally. A very large proportion of personal computers regularly connect to the Internet to communicate and receive information. "Wireless" networking, often utilizing mobile phone networks, has meant networking is becoming increasingly ubiquitous even in mobile computing environments.

Further topics

Hardware

Main article: Computer hardware

The term hardware covers all of those parts of a computer that are tangible objects. Circuits, displays, power supplies, cables, keyboards, printers and mice are all hardware.

**History of computing hardware**
First Generation (Mechanical/Electromechanical)	Calculators	Antikythera mechanism, Difference Engine, Norden bombsight
First Generation (Mechanical/Electromechanical)	Programmable Devices	Jacquard loom, Analytical Engine, Harvard Mark I, Z3
Second Generation (Vacuum Tubes)	Calculators	Atanasoff–Berry Computer, IBM 604, UNIVAC 60, UNIVAC 120
Second Generation (Vacuum Tubes)	Programmable Devices	ENIAC, EDSAC, EDVAC, UNIVAC I, IBM 701, IBM 702, IBM 650, Z22
Third Generation (Discrete transistors and SSI, MSI, LSI Integrated circuits)	Mainframes	IBM 7090, IBM 7080, System/360, BUNCH
	Minicomputer	PDP-8, PDP-11, System/32, System/36
Fourth Generation (VLSI integrated circuits)	Minicomputer	VAX, IBM System i
	4-bit microcomputer	Intel 4004, Intel 4040
	8-bit microcomputer	Intel 8008, Intel 8080, Motorola 6800, Motorola 6809, MOS Technology 6502, Zilog Z80
	16-bit microcomputer	8088, Zilog Z8000, WDC 65816/65802
	32-bit microcomputer	80386, Pentium, 68000, ARM architecture
	64-bit microcomputer^[16]	x86-64, PowerPC, MIPS, SPARC
	Embedded computer	8048, 8051
	Personal computer	Desktop computer, Home computer, Laptop computer, Personal digital assistant (PDA), Portable computer, Tablet computer, Wearable computer
Theoretical/experimental	Quantum computer, Chemical computer, DNA computing, Optical computer, Spintronics based computer

**Other Hardware Topics**
Peripheral device (Input/output)	Input	Mouse, Keyboard, Joystick, Image scanner
	Output	Monitor, Printer
	Both	Floppy disk drive, Hard disk, Optical disc drive, Teleprinter
Computer busses	Short range	RS-232, SCSI, PCI, USB
Computer busses	Long range (Computer networking)	Ethernet, ATM, FDDI

Software

Main article: Computer software

Software refers to parts of the computer which do not have a material form, such as programs, data, protocols, etc. When software is stored in hardware that cannot easily be modified (such as BIOS ROM in an IBM PC compatible), it is sometimes called "firmware" to indicate that it falls into an uncertain area somewhere between hardware and software.

**Computer software**
Operating system	Unix/BSD	UNIX System V, AIX, HP-UX, Solaris (SunOS), IRIX, List of BSD operating systems
	GNU/Linux	List of Linux distributions, Comparison of Linux distributions
	Microsoft Windows	Windows 95, Windows 98, Windows NT, Windows XP, Windows Vista, Windows CE
	DOS	86-DOS (QDOS), PC-DOS, MS-DOS, FreeDOS
	Mac OS	Mac OS classic, Mac OS X
	Embedded and real-time	List of embedded operating systems
	Experimental	Amoeba, Oberon/Bluebottle, Plan 9 from Bell Labs
Library	Multimedia	DirectX, OpenGL, OpenAL
Library	Programming library	C standard library, Standard template library
Data	Protocol	TCP/IP, Kermit, FTP, HTTP, SMTP
Data	File format	HTML, XML, JPEG, MPEG, PNG
User interface	Graphical user interface (WIMP)	Microsoft Windows, GNOME, KDE, QNX Photon, CDE, GEM
User interface	Text user interface	Command line interface, shells
Application	Office suite	Word processing, Desktop publishing, Presentation program, Database management system, Scheduling & Time management, Spreadsheet, Accounting software
	Internet Access	Browser, E-mail client, Web server, Mail transfer agent, Instant messaging
	Design and manufacturing	Computer-aided design, Computer-aided manufacturing, Plant management, Robotic manufacturing, Supply chain management
	Graphics	Raster graphics editor, Vector graphics editor, 3D modeler, Animation editor, 3D computer graphics, Video editing, Image processing
	Audio	Digital audio editor, Audio playback, Mixing, Audio synthesis, Computer music
	Software Engineering	Compiler, Assembler, Interpreter, Debugger, Text Editor, Integrated development environment, Performance analysis, Revision control, Software configuration management
	Educational	Edutainment, Educational game, Serious game, Flight simulator
	Games	Strategy, Arcade, Puzzle, Simulation, First-person shooter, Platform, Massively multiplayer, Interactive fiction
	Misc	Artificial intelligence, Antivirus software, Malware scanner, Installer/Package management systems, File manager

Programming languages

Programming languages provide various ways of specifying programs for computers to run. Unlike natural languages, programming languages are designed to permit no ambiguity and to be concise. They are purely written languages and are often difficult to read aloud. They are generally either translated into machine language by a compiler or an assembler before being run, or translated directly at run time by an interpreter. Sometimes programs are executed by a hybrid method of the two techniques. There are thousands of different programming languages—some intended to be general purpose, others useful only for highly specialized applications.

**Programming Languages**
Lists of programming languages	Timeline of programming languages, Categorical list of programming languages, Generational list of programming languages, Alphabetical list of programming languages, Non-English-based programming languages
Commonly used Assembly languages	ARM, MIPS, x86
Commonly used High level languages	BASIC, C, C++, C#, COBOL, Fortran, Java, Lisp, Pascal
Commonly used Scripting languages	Bourne script, JavaScript, Python, Ruby, PHP, Perl

Professions and organizations

As the use of computers has spread throughout society, there are an increasing number of careers involving computers. Following the theme of hardware, software and firmware, the brains of people who work in the industry are sometimes known irreverently as wetware or "meatware".

**Computer-related professions**
Hardware-related	Electrical engineering, Electronics engineering, Computer engineering, Telecommunications engineering, Optical engineering, Nanoscale engineering
Software-related	Computer science, Human-computer interaction, Information technology, Software engineering, Scientific computing, Web design, Desktop publishing

The need for computers to work well together and to be able to exchange information has spawned the need for many standards organizations, clubs and societies of both a formal and informal nature.

**Organizations**
Standards groups	ANSI, IEC, IEEE, IETF, ISO, W3C
Professional Societies	ACM, ACM Special Interest Groups, IET, IFIP
Free/Open source software groups	Free Software Foundation, Mozilla Foundation, Apache Software Foundation

History of the Internet

2008-01-26T16:03:00.000+07:00

In the 1950s and early 1960s, prior to the widespread inter-networking that led to the Internet, most communication networks were limited by their nature to only allow communications between the stations on the network. Some networks had gateways or bridges between them, but these bridges were often limited or built specifically for a single use. One prevalent computer networking method was based on the central mainframe method, simply allowing its terminals to be connected via long leased lines. This method was used in the 1950s by Project RAND to support researchers such as Herbert Simon, in Pittsburgh, Pennsylvania, when collaborating across the continent with researchers in Sullivan, Illinois, on automated theorem proving and artificial intelligence.

Three terminals and an ARPA

Advanced Research Projects Agency was renamed to Defense Advanced Research Projects Agency (DARPA) in 1972. A fundamental pioneer in the call for a global network, J.C.R. Licklider, articulated the ideas in his January 1960 paper, Man-Computer Symbiosis.

"A network of such [computers], connected to one another by wide-band communication lines" which provided "the functions of present-day libraries together with anticipated advances in information storage and retrieval and [other] symbiotic functions. "—J.C.R. Licklider^[1]

In October 1962, Licklider was appointed head of the United States Department of Defense's DARPA information processing office, and formed an informal group within DARPA to further computer research. As part of the information processing office's role, three network terminals had been installed: one for System Development Corporation in Santa Monica, one for Project Genie at the University of California, Berkeley and one for the Multics project SHOPPING at the Massachusetts Institute of Technology (MIT). Licklider's need for inter-networking would be made evident by the problems this caused.

"For each of these three terminals, I had three different sets of user commands. So if I was talking online with someone at S.D.C. and I wanted to talk to someone I knew at Berkeley or M.I.T. about this, I had to get up from the S.D.C. terminal, go over and log into the other terminal and get in touch with them.

I said, it's obvious what to do (But I don't want to do it): If you have these three terminals, there ought to be one terminal that goes anywhere you want to go where you have interactive computing. That idea is the ARPAnet." - Robert W. Taylor, co-writer with Licklider of "The Computer as a Communications Device", in an interview with the New York Times^[2]

[edit] Packet Switching

Main article: Packet switching

At the tip of the inter-networking problem lay the issue of connecting separate physical networks to form one logical network, with much wasted capacity inside the assorted separate networks. During the 1960s, Donald Davies (NPL), Paul Baran (RAND Corporation), and Leonard Kleinrock (MIT) developed and implemented packet switching. The notion that the Internet was developed to survive a nuclear attack has its roots in the early theories developed by RAND, but is an urban legend, not supported by any Internet Engineering Task Force or other document. Early networks used for the command and control of nuclear forces were message switched, not packet-switched, although current strategic military networks are, indeed, packet-switching and connectionless. Baran's research had approached packet switching from studies of decentralisation to avoid combat damage compromising the entire network.^[3]

[edit] Networks that led to the Internet

[edit] X.25 and public access

Main articles: X.25, Bulletin board system, and FidoNet

Following on from ARPA's research, packet switching network standards were developed by the International Telecommunication Union (ITU) in the form of X.25 and related standards. In 1974, X.25 formed the basis for the SERCnet network between British academic and research sites, which later became JANET. The initial ITU Standard on X.25 was approved in March 1976. This standard was based on the concept of virtual circuits.

The British Post Office, Western Union International and Tymnet collaborated to create the first international packet switched network, referred to as the International Packet Switched Service (IPSS), in 1978. This network grew from Europe and the US to cover Canada, Hong Kong and Australia by 1981. By the 1990s it provided a worldwide networking infrastructure.^[4]

Unlike ARPAnet, X.25 was also commonly available for business use. Telenet offered its Telemail electronic mail service, but this was oriented to enterprise use rather than the general email of ARPANET.

The first dial-in public networks used asynchronous TTY terminal protocols to reach a concentrator operated by the public network. Some public networks, such as CompuServe used X.25 to multiplex the terminal sessions into their packet-switched backbones, while others, such as Tymnet, used proprietary protocols. In 1979, CompuServe became the first service to offer electronic mail capabilities and technical support to personal computer users. The company broke new ground again in 1980 as the first to offer real-time chat with its CB Simulator. There were also the America Online (AOL) and Prodigy dial in networks and many bulletin board system (BBS) networks such as FidoNet. FidoNet in particular was popular amongst hobbyist computer users, many of them hackers and amateur radio operators.

[edit] UUCP

Main articles: UUCP and Usenet

In 1979, two students at Duke University, Tom Truscott and Jim Ellis, came up with the idea of using simple Bourne shell scripts to transfer news and messages on a serial line with nearby University of North Carolina at Chapel Hill. Following public release of the software, the mesh of UUCP hosts forwarding on the Usenet news rapidly expanded. UUCPnet, as it would later be named, also created gateways and links between FidoNet and dial-up BBS hosts. UUCP networks spread quickly due to the lower costs involved, and ability to use existing leased lines, X.25 links or even ARPANET connections. By 1981 the number of UUCP hosts had grown to 550, nearly doubling to 940 in 1984.

[edit] Merging the networks and creating the Internet

[edit] TCP/IP

Main article: Internet protocol suite

Map of the TCP/IP test network in January 1982

With so many different network methods, something was needed to unify them. Robert E. Kahn of DARPA and ARPANET recruited Vinton Cerf of Stanford University to work with him on the problem. By 1973, they had soon worked out a fundamental reformulation, where the differences between network protocols were hidden by using a common internetwork protocol, and instead of the network being responsible for reliability, as in the ARPANET, the hosts became responsible. Cerf credits Hubert Zimmerman, Gerard LeLann and Louis Pouzin (designer of the CYCLADES network) with important work on this design.^[5]

At this time, the earliest known use of the term Internet was by Vinton Cerf, who wrote:

“

Specification of Internet Transmission Control Program.

”

"Request for Comments No. 675" (Network Working Group, electronic text (1974) ^[6]

With the role of the network reduced to the bare minimum, it became possible to join almost any networks together, no matter what their characteristics were, thereby solving Kahn's initial problem. DARPA agreed to fund development of prototype software, and after several years of work, the first somewhat crude demonstration of a gateway between the Packet Radio network in the SF Bay area and the ARPANET was conducted. On November 22, 1977^[7] a three network demonstration was conducted including the ARPANET, the Packet Radio Network and the Atlantic Packet Satellite network—all sponsored by DARPA. Stemming from the first specifications of TCP in 1974, TCP/IP emerged in mid-late 1978 in nearly final form. By 1981, the associated standards were published as RFCs 791, 792 and 793 and adopted for use. DARPA sponsored or encouraged the development of TCP/IP implementations for many operating systems and then scheduled a migration of all hosts on all of its packet networks to TCP/IP. On 1 January 1983, TCP/IP protocols became the only approved protocol on the ARPANET, replacing the earlier NCP protocol.^[8]

[edit] ARPANET to Several Federal Wide Area Networks: MILNET, NSI, and NSFNet

Main articles: ARPANET and NSFNet

After the ARPANET had been up and running for several years, ARPA looked for another agency to hand off the network to; ARPA's primary mission was funding cutting edge research and development, not running a communications utility. Eventually, in July 1975, the network had been turned over to the Defense Communications Agency, also part of the Department of Defense. In 1983, the U.S. military portion of the ARPANET was broken off as a separate network, the MILNET. MILNET subsequently became the unclassified but military-only NIPRNET, in parallel with the SECRET-level SIPRNET and JWICS for TOP SECRET and above. NIPRNET does have controlled security gateways to the public Internet.

The networks based around the ARPANET were government funded and therefore restricted to noncommercial uses such as research; unrelated commercial use was strictly forbidden. This initially restricted connections to military sites and universities. During the 1980s, the connections expanded to more educational institutions, and even to a growing number of companies such as Digital Equipment Corporation and Hewlett-Packard, which were participating in research projects or providing services to those who were.

Several other branches of the U.S. government, the National Aeronautics and Space Agency (NASA), the National Science Foundation (NSF), and the Department of Energy (DOE) became heavily involved in internet research and started development of a successor to ARPANET. In the mid 1980s all three of these branches developed the first Wide Area Networks based on TCP/IP. NASA developed the NASA Science Network, NSF developed CSNET and DOE evolved the Energy Sciences Network or ESNet.

More explicitly, NASA developed a TCP/IP based Wide Area Network, NASA Science Network (NSN), in the mid 1980s connecting space scientists to data and information stored anywhere in the world. In 1989, the DECnet-based Space Physics Analysis Network (SPAN) and the TCP/IP-based NASA Science Network (NSN) were brought together at NASA Ames Research Center creating the first multiprotocol wide area network called the NASA Science Internet, or NSI. NSI was established to provide a total integrated communications infrastructure to the NASA scientific community for the advancement of earth, space and life sciences. As a high-speed, multiprotocol, international network, NSI provided connectivity to over 20,000 scientists across all seven continents.

In 1984 NSF developed CSNET exclusively based on TCP/IP. CSNET connected with ARPANET using TCP/IP, and ran TCP/IP over X.25, but it also supported departments without sophisticated network connections, using automated dial-up mail exchange. This grew into the NSFNet backbone, established in 1986, and intended to connect and provide access to a number of supercomputing centers established by the NSF.^[9]

[edit] The transition toward an Internet

The term "Internet" was adopted in the first RFC published on the TCP protocol (RFC 675[1]: Internet Transmission Control Program, December 1974). It was around the time when ARPANET was interlinked with NSFNet, that the term Internet came into more general use,^[10] with "an internet" meaning any network using TCP/IP. "The Internet" came to mean a global and large network using TCP/IP. Previously "internet" and "internetwork" had been used interchangeably, and "internet protocol" had been used to refer to other networking systems such as Xerox Network Services.^[11]

As interest in wide spread networking grew and new applications for it arrived, the Internet's technologies spread throughout the rest of the world. TCP/IP's network-agnostic approach meant that it was easy to use any existing network infrastructure, such as the IPSS X.25 network, to carry Internet traffic. In 1984, University College London replaced its transatlantic satellite links with TCP/IP over IPSS.

Many sites unable to link directly to the Internet started to create simple gateways to allow transfer of e-mail, at that time the most important application. Sites which only had intermittent connections used UUCP or FidoNet and relied on the gateways between these networks and the Internet. Some gateway services went beyond simple e-mail peering, such as allowing access to FTP sites via UUCP or e-mail.

[edit] TCP/IP becomes worldwide

The first ARPANET connection outside the US was established to NORSAR in Norway in 1973, just ahead of the connection to Great Britain. These links were all converted to TCP/IP in 1982, at the same time as the rest of the Arpanet.

[edit] CERN, the European internet, the link to the Pacific and beyond

Between 1984 and 1988 CERN began installation and operation of TCP/IP to interconnect its major internal computer systems, workstations, PC's and an accelerator control system. CERN continued to operate a limited self-developed system CERNET internally and several incompatible (typically proprietary) network protocols externally. There was considerable resistance in Europe towards more widespread use of TCP/IP and the CERN TCP/IP intranets remained isolated from the rest of the Internet until 1989.

In 1988 Daniel Karrenberg, from CWI in Amsterdam, visited Ben Segal, CERN's TCP/IP Coordinator, looking for advice about the transition of the European side of the UUCP Usenet network (much of which ran over X.25 links) over to TCP/IP. In 1987, Ben Segal had met with Len Bosack from the then still small company Cisco about purchasing some TCP/IP routers for CERN, and was able to give Karrenberg advice and forward him on to Cisco for the appropriate hardware. This expanded the European portion of the Internet across the existing UUCP networks, and in 1989 CERN opened its first external TCP/IP connections.^[12] This coincided with the creation of Réseaux IP Européens (RIPE), initially a group of IP network administrators who met regularly to carry out co-ordination work together. Later, in 1992, RIPE was formally registered as a cooperative in Amsterdam.

At the same time as the rise of internetworking in Europe, adhoc networking to ARPA and in-between Australian universities formed, based on various technologies such as X.25 and UUCPNet. These were limited in their connection to the global networks, due to the cost of making individual international UUCP dial-up or X.25 connections. In 1989, Australian universities joined the push towards using IP protocols to unify their networking infrastructures. AARNet was formed in 1989 by the Australian Vice-Chancellors' Committee and provided a dedicated IP based network for Australia.

The Internet began to penetrate Asia in the late 1980s. Japan, which had built the UUCP-based network JUNET in 1984, connected to NSFNet in 1989. It hosted the annual meeting of the Internet Society, INET'92, in Kobe. Singapore developed TECHNET in 1990, and Thailand gained a global Internet connection between Chulalongkorn University and UUNET in 1992.^[13]

[edit] A digital divide

Main article: Digital divide

While developed countries with technological infrastructures were joining the Internet, developing countries began to experience a digital divide separating them from the Internet. On an essentially continental basis, they are building organizations for Internet resource administration and sharing operational experience, as more and more transmission facilities go into place.

[edit] Africa

At the beginning of the 1990s, African countries relied upon X.25 IPSS and 2400 baud modem UUCP links for international and internetwork computer communications. In 1996 a USAID funded project, the Leland initiative, started work on developing full Internet connectivity for the continent. Guinea, Mozambique, Madagascar and Rwanda gained satellite earth stations in 1997, followed by Côte d'Ivoire and Benin in 1998.

Africa is building an Internet infrastructure. AfriNIC, headquartered in Mauritius, manages IP address allocation for the continent. As do the other Internet regions, there is an operational forum, the Internet Community of Operational Networking Specialists.^[14]

There are a wide range of programs both to provide high-performance transmission plant, and the western and southern coasts have undersea optical cable. High-speed cables join North Africa and the Horn of Africa to intercontinental cable systems. Undersea cable development is slower for East Africa; the original joint effort between New Partnership for Africa's Development (NEPAD) and the East Africa Submarine System (Eassy) has broken off and may become two efforts.^[15]

[edit] Asia and Oceania

The Asia Pacific Network Information Centre (APNIC), headquartered in Australia, manages IP address allocation for the continent. APNIC sponsors an operational forum, the Asia-Pacific Regional Internet Conference on Operational Technologies (APRICOT).^[16]

In 1991, the People's Republic of China saw its first TCP/IP college network, Tsinghua University's TUNET. The PRC went on to make its first global Internet connection in 1995, between the Beijing Electro-Spectrometer Collaboration and Stanford University's Linear Accelerator Center. However, China went on to implement its own digital divide by implementing a country-wide content filter.^[17]

[edit] Latin America

As with the other regions, the Latin American and Caribbean Internet Addresses Registry (LACNIC) manages the IP address space and other resources for its area. LACNIC, headquartered in Uruguay, operates DNS root, reverse DNS, and other key services.

[edit] Opening the network to commerce

The interest in commercial use of the Internet became a hotly debated topic. Although commercial use was forbidden, the exact definition of commercial use could be unclear and subjective. UUCPNet and the X.25 IPSS had no such restrictions, which would eventually see the official barring of UUCPNet use of ARPANET and NSFNet connections. Some UUCP links still remained connecting to these networks however, as administrators cast a blind eye to their operation.

During the late 1980s, the first Internet service provider (ISP) companies were formed. Companies like PSINet, UUNET, Netcom, and Portal Software were formed to provide service to the regional research networks and provide alternate network access, UUCP-based email and Usenet News to the public. The first dial-up in the West Coast, was Best Internet[2] - now Verio Communications, opened in 1986. The first dialup ISP in the East was world.std.com, opened in 1989.

This caused controversy amongst university users, who were outraged at the idea of noneducational use of their networks. Eventually, it was the commercial Internet service providers who brought prices low enough that junior colleges and other schools could afford to participate in the new arenas of education and research.

By 1990, ARPANET had been overtaken and replaced by newer networking technologies and the project came to a close. In 1994, the NSFNet, now renamed ANSNET (Advanced Networks and Services) and allowing non-profit corporations access, lost its standing as the backbone of the Internet. Both government institutions and competing commercial providers created their own backbones and interconnections. Regional network access points (NAPs) became the primary interconnections between the many networks and the final commercial restrictions ended.

[edit] The IETF and a standard for standards

Main article: IETF

The Internet has developed a significant subculture dedicated to the idea that the Internet is not owned or controlled by any one person, company, group, or organization. Nevertheless, some standardization and control is necessary for the system to function.

The liberal Request for Comments (RFC) publication procedure engendered confusion about the Internet standardization process, and led to more formalization of official accepted standards. The IETF started in January of 1985 as a quarterly meeting of U.S. government funded researchers. Representatives from non-government vendors were invited starting with the fourth IETF meeting in October of that year.

Acceptance of an RFC by the RFC Editor for publication does not automatically make the RFC into a standard. It may be recognized as such by the IETF only after experimentation, use, and acceptance have proved it to be worthy of that designation. Official standards are numbered with a prefix "STD" and a number, similar to the RFC naming style. However, even after becoming a standard, most are still commonly referred to by their RFC number.

In 1992, the Internet Society, a professional membership society, was formed and the IETF was transferred to operation under it as an independent international standards body.

[edit] NIC, InterNIC, IANA and ICANN

Main articles: InterNIC, Internet Assigned Numbers Authority, and ICANN

The first central authority to coordinate the operation of the network was the Network Information Centre (NIC) at Stanford Research Institute (SRI) in Menlo Park, California. In 1972, management of these issues was given to the newly created Internet Assigned Numbers Authority (IANA). In addition to his role as the RFC Editor, Jon Postel worked as the manager of IANA until his death in 1998.

As the early ARPANET grew, hosts were referred to by names, and a HOSTS.TXT file would be distributed from SRI International to each host on the network. As the network grew, this became cumbersome. A technical solution came in the form of the Domain Name System, created by Paul Mockapetris. The Defense Data Network—Network Information Center (DDN-NIC) at SRI handled all registration services, including the top-level domains (TLDs) of .mil, .gov, .edu, .org, .net, .com and .us, root nameserver administration and Internet number assignments under a United States Department of Defense contract.^[18] In 1991, the Defense Information Systems Agency (DISA) awarded the administration and maintenance of DDN-NIC (managed by SRI up until this point) to Government Systems, Inc., who subcontracted it to the small private-sector Network Solutions, Inc.^[19] ^[20]

Since at this point in history most of the growth on the Internet was coming from non-military sources, it was decided that the Department of Defense would no longer fund registration services outside of the .mil TLD. In 1993 the U.S. National Science Foundation, after a competitive bidding process in 1992, created the InterNIC to manage the allocations of addresses and management of the address databases, and awarded the contract to three organizations. Registration Services would be provided by Network Solutions; Directory and Database Services would be provided by AT&T; and Information Services would be provided by General Atomics.^[21]

In 1998 both IANA and InterNIC were reorganized under the control of ICANN, a California non-profit corporation contracted by the US Department of Commerce to manage a number of Internet-related tasks. The role of operating the DNS system was privatized and opened up to competition, while the central management of name allocations would be awarded on a contract tender basis.

[edit] Use and culture

[edit] Email and Usenet—The growth of the text forum

Main articles: e-mail and Usenet

E-mail is often called the killer application of the Internet. However, it actually predates the Internet and was a crucial tool in creating it. E-mail started in 1965 as a way for multiple users of a time-sharing mainframe computer to communicate. Although the history is unclear, among the first systems to have such a facility were SDC's Q32 and MIT's CTSS.^[22]

The ARPANET computer network made a large contribution to the evolution of e-mail. There is one report^[23] indicating experimental inter-system e-mail transfers on it shortly after ARPANET's creation. In 1971 Ray Tomlinson created what was to become the standard Internet e-mail address format, using the @ sign to separate user names from host names.^[24]

A number of protocols were developed to deliver e-mail among groups of time-sharing computers over alternative transmission systems, such as UUCP and IBM's VNET e-mail system. E-mail could be passed this way between a number of networks, including ARPANET, BITNET and NSFNet, as well as to hosts connected directly to other sites via UUCP.

In addition, UUCP allowed the publication of text files that could be read by many others. The News software developed by Steve Daniel and Tom Truscott in 1979 was used to distribute news and bulletin board-like messages. This quickly grew into discussion groups, known as newsgroups, on a wide range of topics. On ARPANET and NSFNet similar discussion groups would form via mailing lists, discussing both technical issues and more culturally focused topics (such as science fiction, discussed on the sflovers mailing list).

[edit] A world library—From gopher to the WWW

Main articles: History of the World Wide Web and World Wide Web

As the Internet grew through the 1980s and early 1990s, many people realized the increasing need to be able to find and organize files and information. Projects such as Gopher, WAIS, and the FTP Archive list attempted to create ways to organize distributed data. Unfortunately, these projects fell short in being able to accommodate all the existing data types and in being able to grow without bottlenecks.^{[citation needed]}

One of the most promising user interface paradigms during this period was hypertext. The technology had been inspired by Vannevar Bush's "Memex"^[25] and developed through Ted Nelson's research on Project Xanadu and Douglas Engelbart's research on NLS.^[26] Many small self-contained hypertext systems had been created before, such as Apple Computer's HyperCard. Gopher became the first commonly-used hypertext interface to the Internet. While Gopher menu items were examples of hypertext, they were not commonly perceived in that way.

In 1989, whilst working at CERN, Tim Berners-Lee invented a network-based implementation of the hypertext concept. By releasing his invention to public use, he ensured the technology would become widespread.^[27]. One early popular web browser, modeled after HyperCard, was ViolaWWW.

Scholars generally agree,^{[citation needed]} however, that the turning point for the World Wide Web began with the introduction^[28] of the Mosaic web browser^[29] in 1993, a graphical browser developed by a team at the National Center for Supercomputing Applications at the University of Illinois at Urbana-Champaign (NCSA-UIUC), led by Marc Andreessen. Funding for Mosaic came from the High-Performance Computing and Communications Initiative, a funding program initiated by then-Senator Al Gore's High Performance Computing and Communication Act of 1991 also known as the Gore Bill .^[30] Indeed, Mosaic's graphical interface soon became more popular than Gopher, which at the time was primarily text-based, and the WWW became the preferred interface for accessing the Internet. (Gore's reference to his role in "creating the Internet", however, was ridiculed in his Presidential election campaign: see full article Al Gore contributions to the internet and technology).

Mosaic was eventually superseded in 1994 by Andreessen's Netscape Navigator, which replaced Mosaic as the world's most popular browser. While it held this title for some time, eventually competition from Internet Explorer and a variety of other browsers almost completely displaced it. Another important event held on January 11, 1994, was The Superhighway Summit at UCLA's Royce Hall. This was the "first public conference bringing together all of the major industry, government and academic leaders in the field [and] also began the national dialogue about the Information Superhighway and its implications."^[31]

24 Hours in Cyberspace, the "the largest one-day online event" (February 8, 1996) up to that date, took place on the then-active website, cyber24.com.^[32]^[33] It was headed by photographer Rick Smolan.^[34] A photographic exhibition was unveiled at the Smithsonian Institution's National Museum of American History on 23 January 1997, featuring 70 photos from the project.^[35]

[edit] Finding what you need—The search engine

Main article: Search engine

Even before the World Wide Web, there were search engines that attempted to organize the Internet. The first of these was the Archie search engine from McGill University in 1990, followed in 1991 by WAIS and Gopher. All three of those systems predated the invention of the World Wide Web but all continued to index the Web and the rest of the Internet for several years after the Web appeared. There are still Gopher servers as of 2006, although there are a great many more web servers.

As the Web grew, search engines and Web directories were created to track pages on the Web and allow people to find things. The first full-text Web search engine was WebCrawler in 1994. Before WebCrawler, only Web page titles were searched. Another early search engine, Lycos, was created in 1993 as a university project, and was the first to achieve commercial success. During the late 1990s, both Web directories and Web search engines were popular—Yahoo! (founded 1995) and Altavista (founded 1995) were the respective industry leaders.

By August 2001, the directory model had begun to give way to search engines, tracking the rise of Google (founded 1998), which had developed new approaches to relevancy ranking. Directory features, while still commonly available, became after-thoughts to search engines.

Database size, which had been a significant marketing feature through the early 2000s, was similarly displaced by emphasis on relevancy ranking, the methods by which search engines attempt to sort the best results first. Relevancy ranking first became a major issue circa 1996, when it became apparent that it was impractical to review full lists of results. Consequently, algorithms for relevancy ranking have continuously improved. Google's PageRank method for ordering the results has received the most press, but all major search engines continually refine their ranking methodologies with a view toward improving the ordering of results. As of 2006, search engine rankings are more important than ever, so much so that an industry has developed ("search engine optimizers", or "SEO") to help web-developers improve their search ranking, and an entire body of case law has developed around matters that affect search engine rankings, such as use of trademarks in metatags. The sale of search rankings by some search engines has also created controversy among librarians and consumer advocates.

[edit] The dot-com bubble

Main article: Dot-com bubble

The suddenly low price of reaching millions worldwide, and the possibility of selling to or hearing from those people at the same moment when they were reached, promised to overturn established business dogma in advertising, mail-order sales, customer relationship management, and many more areas. The web was a new killer app—it could bring together unrelated buyers and sellers in seamless and low-cost ways. Visionaries around the world developed new business models, and ran to their nearest venture capitalist. Of course a proportion of the new entrepreneurs were truly talented at business administration, sales, and growth; but the majority were just people with ideas, and didn't manage the capital influx prudently. Additionally, many dot-com business plans were predicated on the assumption that by using the Internet, they would bypass the distribution channels of existing businesses and therefore not have to compete with them; when the established businesses with strong existing brands developed their own Internet presence, these hopes were shattered, and the newcomers were left attempting to break into markets dominated by larger, more established businesses. Many did not have the ability to do so.

The dot-com bubble burst on March 10, 2000, when the technology heavy NASDAQ Composite index peaked at 5048.62 (intra-day peak 5132.52), more than double its value just a year before. By 2001, the bubble's deflation was running full speed. A majority of the dot-coms had ceased trading, after having burnt through their venture capital, often without ever making a gross profit.

[edit] Worldwide Online Population Forecast

In its "Worldwide Online Population Forecast, 2006 to 2011," JupiterResearch anticipates that a 38 percent increase in the number of people with online access will mean that, by 2011, 22 percent of the Earth's population will surf the Internet regularly.

JupiterResearch says the worldwide online population will increase at a compound annual growth rate of 6.6 percent during the next five years, far outpacing the 1.1 percent compound annual growth rate for the planet's population as a whole. The report says 1.1 billion people currently enjoy regular access to the Web.

North America will remain on top in terms of the number of people with online access. According to JupiterResearch, online penetration rates on the continent will increase from the current 70 percent of the overall North American population to 76 percent by 2011. However, Internet adoption has "matured," and its adoption pace has slowed, in more developed countries including the United States, Canada, Japan and much of Western Europe, notes the report.

As the online population of the United States and Canada grows by about only 3 percent, explosive adoption rates in China and India will take place, says JupiterResearch. The report says China should reach an online penetration rate of 17 percent by 2011 and India should hit 7 percent during the same time frame. This growth is directly related to infrastructure development and increased consumer purchasing power, notes JupiterResearch.

By 2011, Asians will make up about 42 percent of the world's population with regular Internet access, 5 percent more than today, says the study.

Penetration levels similar to North America's are found in Scandinavia and bigger Western European nations such as the United Kingdom and Germany, but JupiterResearch says that a number of Central European countries "are relative Internet laggards."

Brazil "with its soaring economy," is predicted by JupiterResearch to experience a 9 percent compound annual growth rate, the fastest in Latin America, but China and India are likely to do the most to boost the world's online penetration in the near future.

For the study, JupiterResearch defined "online users" as people who regularly access the Internet by "dedicated Internet access" devices. Those devices do not include cell phones.^[36]

How To Browse The Web In China When Your Favorite Sites Are Blocked

2008-01-26T15:59:00.003+07:00

If you want to see the differences between Google’s top level domains, try Google’s Image search from 2 different URLs:

images.google.com
images.google.cn

Type in the Search box: “Tian'anmen Square massacre” or “Tian An Men Square massacre”. Ironically, this translates to “Gate of Heavenly Peace”.

Convinced?

It is well known that in China, certain websites like BBC and CNN are blocked. But you can get around it by use of a Proxy Server.

What is a Proxy Server?

A Proxy Server services requests from clients by forwarding requests to other servers.

If you are computer “C”, and you want to access server “S” but it is blocked, point your client’s web browser to Proxy Server “P”.

So C -> P -> S

An example of such a site is www.kproxy.com (ignore the pop-up windows) but if you search the web for proxy servers, you can have a list of thousands. Some are even more specific on what services you want enabled or disabled, such as removing JavaScript, enabling cookies, or displaying images.

As long as your network connection’s ISP isn’t blocking the Proxy Server, you can get access to those sites. And some get creative by using another standard HTTP port 80. Ports 8080 or 8081 are the most common, so you would enter proxyserver.com:8080 for the URL.

Circumventor Proxy server

A Circumventor is a Proxy servers used for defeating blocking policies implemented by an organization or country when “censorship” blocks access to certain sites. Of course, having a known list of proxy servers beforehand would be really helpful if you are planning a trip to such countries with censorship.

Anonymizing Proxy server

On the other hand, if I was an employee and wanted to check out my competition without them tracking my IP address, then this is an example of an Anonymizing proxy server.

An Anonymizing Proxy server is the correct term for the purpose of anonymity and is an alternate way using your AOL dialup account. Besides, you want to take advantage of your high speed Internet connection, don’t you?

Reverse Proxy Server?

The reverse holds true with a reverse proxy server. Your corporate firewall may have a proxy server where everyone’s internal computer points to a central proxy server, and that server goes out and services requests.

Pros: it does speed up surfing for users, as it caches web site information and images from previously searched sites. It would also reduce the traffic, as the information is already stored and no need to go the destination site again. As well, the proxy server adds an additional level of security next to your corporate firewall.

Cons: your company can track every site you surf, and how long you stay on that particular site. Not good if you spend all day checking your hockey pool stats, or surfing questionable sites.

Open Proxies

Caution should be taken as Open Proxies are usually abused for sending spam or even hacking into your own machine. You have no idea what is on the server, including keystroke trackers to capture your keyboard input. So the next time you enter your user ID and password on one of these open proxies, think again.

I hope this sheds some light on ways to get around censorship.

Free Spyware Removal Software - Why Use It?

2008-01-26T15:59:00.001+07:00

I guess most of us have been bothered with spyware infections once or more. Nobody likes that their computer become slow because of them, and nobody likes to pay a huge pile of cash just to get rid of them either. In this article I write about a great spyware removal tool that is free. What you get for zero bucks could sometimes actually be a whole lot.

When people get infections into their home computer, many are not aware of the existence of such threats. They just keep on working with their slow running computers until they stop almost completely. Some ask friends or relatives with a little computer experience to take a look at their computer. Therefore I will try to explain the importance of having protection, and how to get something that works.

Through the two latest decades we have seen computers eventually come into our lives, and that we use them more and more, and integrate them to become more or less a necessity in our homes. But, when internet was made public in 1990 we also began to see more and more of all the problems that came along with it.

An experience that I've had often is, when a system was near a breakdown, the problems was very often caused by a massive infection of online threats. Today we know them as spyware, adware, worms, trojan horses or viruses. They crawl up your cables and into your system, and when they become many they start competing with eachother for the available resources.

This will cause the computer to slow down, and when it eventually comes to a complete stop, the number of nfections will be too high for the computer to handle. All the power you need to do your stuff will be unavailable. An overrun system is of no real value to the user, because there are virtually no resources left to run real programs. This computer system has also become a real danger to privacy.

A good security tool could get rid of these bugs. I recommend that you have three basic types of security software installed on your system. Number one is a firewall protection. This will help prevent hackers from breaking into your system. Number two is a good antivirus solution. This keeps viruses, worms, trojan horses and often other types of threats away. Number three is to have a good spyware removal tool, because these threats are the most common ones today. They spread between computers like wildfire. Some of them are even made to steal your private information.

A quality piece of security software would protect you from various types of threats. But no software will make your system total immune, and a combination of different pieces of quality software is always preferred.

No matter what, it is always better to atleast have somekind of protection software installed, rather than nothing at all. So you might need to look for some you too. A good place to do this is online. This is because you simply get the fastest delivery and the best prices. But you have to look carefully for it.

I need to alert you about a new type of threats that is spreading around the world these days. A bug slips into your system, and almost instantly pops up with a warning about a "system error" from something called "Security Center" or similar. You should pay attention to this kind.

They infect you in the first place, then they want you to purchase a remedy for their disease and other types of infections. But most of them don't get rid of anything but the warnings, and even slips more bugs into your computer. Sneaky don't you think?

There are alot of software and solutions to choose from. Some are expensive, some are cheap, some are good and some are worse. They vary as much quality as they vary in price, and the most expensive ones are not by far always the best ones.

Infact there are actually spyware removal software packages that will protect against several categories of threats, and it will even clean up your computer's registry. This feature alone is a good way to increase the computers speed. I know about a really great tool that will do all this for you, and even for free.

This package does unfornately not include a firewall protection, but if you are running Windows XP there is a good firewall included in this operating-system. Just go to the control panel, and then to the Windows security center to activate it. It works great, and you should definately turn it on if you have it in the first place. This firewall in combination with the totally free spyware removal tool we provide on our website, you'll suddenly have a nice protection.

If you see the point of being protected for free rather than not protected, I have met my goal. Take care, and secure your computer properly. More information about this great free tool is to be found at our website.

Protecting Children Online With Internet Parental Controls

2008-01-26T15:58:00.001+07:00

The World Wide Web is a fascinating place. It has obliterated geography in terms of education and business. It facilitates learning by allowing kids to see things and experiences aspects of different places they may never get the chance to see in the non-virtual world. The Internet can bring people together who otherwise would never know each other and create a virtual universe that is totally cohesive, with every kind of information imaginable literally available at your fingertips. Sounds great, doesn’t it?

Unfortunately, the Internet has a dark side. It is full of material that is inappropriate for children and all kinds of predators. Leaving your kids alone to fend for themselves on the Web is exactly as dangerous at leaving them in a crowed airport or shopping mall. You don’t know where they’re going or who with. The news is filled with horror stories about kids who have been taken advantage of on the Internet, but you don’t want yours to miss out on all the positive aspects of the technology. The first line of defense in keeping your kids save on the Web is to teach them how to use it safely.

A lot of online dangers can be dodged simply by reminding kids of one of their earliest learned lessons: don’t talk to strangers. The kinds of people who want to harm kids have all kinds of tricks up their sleeves. They may try to lull your child into a false sense of security by pretending to be someone she knows. Make sure your child understands that it isn’t a good idea to give out personal information such as their address, phone number or the name of their school. The less information a potential predator has, the harder it will be for him to actually locate a victim. It might be a good idea to establish a secret password and share it only with friends and family so your kid has a way to identify people who are safe to chat with.

Chat interfaces and instant messaging are great tools for keeping in touch with friends and conduct business, but they are also direct connections between your child and possible pedophiles and other predators. Most instant messengers have settings that will only allow people on a pre-approved list to approach your child. That way you can let the kids chat with family and friends while keeping the bad guys out. You can visit http://www.internet-parental-control.org to find more information on online child safety measures.

You can’t watch your kids every minute they are online, and you can’t always count on them to do what you have taught them to do. Parental control software is a great back up. Most browsers will allow you to customize age-appropriate settings for each child in your house. You can choose what kinds of Web sites you want your kids to access and block them out of the ones you don’t. It’s a great way to provide a virtual safety net for your family. If the parental controls supplied by your Internet Service Provider, check into installing additional software that will evaluate each site your child attempts to access. You set criteria by which the software judges each Web page and assigns a rating, much like a movie rating. Your kids will only be able to look at sites with ratings you have deemed appropriate.

There Be Spyware Here, Captain!

2008-01-26T15:57:00.002+07:00

The ships bell had just sounded the dogwatch as Captain Skag
began to check his email. He had just began to read his
favorite E-zine, "Pirates gone wild" when his first mate
burst into the cabin. "Captain, a dark ship approaches!"
He cried.

The captain, after running up on deck, examined the ship
with his spyglass. "Shiver me hard drives" he bellowed as
he saw the lay of her jib.

"Shes a wardriver! " (Note of historical Interest, a
Wardriver is a term used to describe a way of searching for
unsecure wireless networks.)

"They be after plundering information on the ships server!
Quick me mateys, prepare to repel boarders." The crew
scrambled to turn their laptops off while the Captain rushed
to turn the wireless router off.

Up on deck, the crew watched as the dark ship faded into the
night.

The Captain had no sooner settled back at his computer when
again the cabin door burst open, this time it was the cook.
"Blimey Captain, all my recipes files are gone!" This was
bad news because the cooks famous secret recipe for chile con carne
was highly sought after since winning 1st place at the
Pirates ball last year. Thank the Kraken we have our
backups" the Captain growled. The cook, cursing, left.

Well, back to my email the captain thought. He pushed the
send/receive button on his email client. "Blow me down" he
bellowed, (Pirate Captains bellow a lot) "Whats all
this SPAM mail doing in my inbox?"

This was getting as back as a case of scurvy.

As he sat, his rage boiling, he became aware of a lot of
yelling coming from the crews quarters. "Now what" he
cursed as he made his way forward. Upon entering the crew
area he was assailed by a thunderous din of curses. (Pirates
curse a lot)

The Spainiard was yelling he couldn't get his new game,
"Pirates Revenge " to load. The Italian couldn't get into his stock portfolio.
(Yes pirates have retirement plans too). The others were
drowned out by the first mate yelling about his Blog being Hacked.

As he surveyed the carnage, the captain noticed one of the
crewman sitting calmly, using his laptop with apparently no
problems. Bellowing loudly for quiet, he asked the crewman
who he now remembered came from the land of Unix, why he was
not upset.

He looked up, and said "Why Captain, I've got a AntiVirus
program along with good AntiSpyware and a reliable Firewall. I'm
protected from brute force attacks, Phishing emails and
drive by downloads." He went on to say that it looked like the ships
server was accessed through the wireless router, which was not
secured with WEP (wired/wireless equivalent privacy).

"Arrrgg", he bellowed, the IT dogs back at the Island
hideaway had told him all was peachy with the network when
they sailed to pilage and plunder.

The crewman whose name was Billy said he could get things
ship shape by giving the other crewman the CD's of his
AntiSpyware, AntiVirus and his 3rd party Firewall.... for a
price! "Aye," the Captain replied wit a feeling of dread,
"Whats your price?"

Soon all onboard were back online and secure. Billy had his
pockets stuffed with pieces of eight and of course, was
wearing the Captains hat, looking mighty pleased with his
bargaining skills.

The Captain headed back to his cabin, worried that mutiny
may be afoot. He had heard Billy telling the crew about those
cursed Macs!

The lesson learned here was obvious; You need to secure your
network. AntiVirus and AntiSpyware is a must, So is a
reliable Firewall. Anything less, you might as well be
walking the plank, Matey!