Shareware is software that is distributed without payment ahead of time as is common for proprietary software. Typically shareware software is obtained free of charge by downloading, thus allowing one to try out the program ahead of time. A shareware program is accompanied by a request for payment, and often payment is required per the terms of the license past a set period of time. The term shareware was coined by Bob Wallace to describe his word processorPC-Write in the mid-1980s.
Open source software and shareware are similar in that they can be obtained and used without monetary cost. Usually shareware differs from 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 not available in a form that would allow others to extend the program. Notwithstanding that tradition, some freeware authors ask for voluntary "donations," although there is no requirement to do so.
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—in which case the software is vernacularly called crippleware.
The original shareware programs were applications running under DOS, but are now more commonly utilities running on Microsoft Windows, although gaming, editing and other examples also exist. Shareware is rarely found on non-MacintoshUnix-like operating systems, which may be due to the corporate use of Unix until the advent of Linux, which championed free software as opposed to shareware, but more likely due to the fact that the Unix/Linux market is very small compared to Microsoft Windows thus drastically reducing the "shareware licensing fee" potential.