"The Doom source code was released to the public on December 23, 1997. Although Doom was originally created for DOS, the release was of the Linux version, and t

"The Doom source code was released to the public on December 23, 1997. Although Doom was originally created for DOS, the release was of the Linux version, and the source code had to be ported back to DOS and to other operating systems. Hence the term "source port", which out of custom also is used for those modifications which are not technically ports to another platform. The term itself originates from the first source port, DOSDoom and its 0.2 version. "[0] Term has been in use since 97, not exactly new. [0]: https://doom.fandom.com/wiki/Source_port https://doom.fandom.com/wiki/Source_port