ABANDONWARE

Abandonware refers to computer software that is no longer sold or supported, or whose ownership may be unclear for various reasons. While the term has been applied largely to older games, other classes of software are sometimes described as such. Definitions of "abandoned" vary; generally, it refers to software no longer available for legitimate purchase or of a certain age. Software companies may change their names, go bankrupt, enter into mergers, or cease to exist for a variety of reasons. When this happens, product rights are usually transferred to another company that might not sell or support the software acquired.
Some companies such as Corel and LucasArts have actively protected the copyright of their past work while others have released it into the public domain.Software can be abandoned when it can only be used with obsolete technologies such as an Amiga, Atari or pre-Macintosh Apple computer. Companies do sometimes voluntarily relinquish copyright on software, putting it into the public domain, or re-license it as free software or freeware. id Software is an early proponent of this practice, releasing the source code for the game engines (but not the actual game content, such as levels or textures) of some older titles under a free software license. Other examples include Amstrad, which supports emulation and free distribution of CPC and ZX Spectrum hardware ROMs and software, and Revolution Software, which released their game Beneath a Steel Sky as freeware and gave the engine's source code to the authors of ScummVM to add support for the game. Transfer of public domain or free software is perfectly legal, distinguishing it from copyrighted abandonware. See list of commercial games released as freeware.
There are groups that lobby companies to release their software as freeware. These efforts have met with mixed results. One example is the library of educational titles released by MECC. MECC was sold to Brøderbund, which was sold to The Learning Company (TLC). When TLC was contacted about releasing classic MECC titles as freeware, the documentation proving that TLC owned the rights to these titles could not be located, and therefore the rights for these titles are "in limbo" and may never be legally released.