The Web abounds in all kinds of software. These may be categorised as freeware, public-domain software and shareware. Many software vendors also make their demo software available for downloading. These usually are programmed to expire after a reasonable trial period of one month or more. In order that we do not infringe copyright, we should have an understanding of the implications in using these software.

Freeware are copyrighted software given away for free by the author. Although it is available for free, the author retains the copyright, which means that you cannot do anything with it that is not expressly allowed by the author. Usually, the author allows people to use the software, but not sell it.

Public-domain software refers to any program that is not copyrighted. It is free and can be used without restrictions.

Shareware is software distributed on the basis of an honor system. Most shareware is delivered free of charge, but the author usually requests that you pay a small fee if you like the program and use it regularly. By sending the small fee, you become registered with the producer so that you can receive service assistance and updates. You can copy shareware and pass it along to friends and colleagues, but they too are expected to pay a fee if they use the product.

Shareware is inexpensive because it is usually produced by a single programmer and is offered directly to customers. Thus, there are practically no packaging or advertising expenses. Note that shareware differs from public-domain software in that shareware is copyrighted. This means that you cannot sell a shareware product as your own.

Popular software sites will normally set up mirror sites with interested institutions or organisations in other countries. A mirror site is a Web site or set of files on a computer server that has been copied to another computer server in order to reduce network traffic, ensure better availability of the Web site or files, or make the site or downloaded files arrive more quickly for users close to the mirror site. A mirror site is an exact replica of the original site and is usually updated frequently to ensure that it reflects the content of the original site. Mirror sites are used ti make access faster when the original site may be geographically distant (for example, a much-used Web site in the States may arrange to have a mirror site in Singapore). In some cases, the original site (for example, on a small university server) may not have a high-speed connection to the Internet and may arrange for a mirror site at a larger site with higher-speed connection and perhaps closer proximity to a large audience.

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