Implementations
Free/open-source software and shareware are similar in that they can be obtained and used without monetary cost. Usually, shareware differs from free/open-source software in that requests of voluntary shareware fees are made, often within the program itself, and in that source code for shareware programs is generally unavailable in a form that would allow others to extend the program. Notwithstanding that tradition, some free/open source software authors ask for voluntary donations, although there is no requirement to do so. Free/open-source software is usually compatible with the strict Association of Software Professionals shareware guidelines.
Sometimes, paying the fee and obtaining a password results in access to expanded features, documentation, or support. In some cases, unpaid use of the software is limited in time or in features – in which case the software is vernacularly called crippleware or trialware. Some titles display a dialog box with payment information and a message that paying will remove the notice, which is usually designed to be annoying to encourage the user to pay; this is termed nagware. Some shareware items require no payment; just an email address, so that the supplier can use this address for their own purposes.
Shareware is available on all major computer platforms, including Microsoft Windows, Macintosh, Linux, and Unix. Titles cover a very wide range of categories including: business, software development, education, home, multimedia, design, drivers, games, and utilities. Because of its minimal overhead and low cost, the shareware model is often the only one practical for distributing non-free software for abandoned or orphaned platforms such as the Atari ST and Amiga.
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