Wikipedia
MicroEMACS
MicroEMACS is a small, portable Emacs-like text editor originally written by Dave Conroy in 1985, and further developed by Daniel M. Lawrence (1958–2010) and was maintained by him. MicroEMACS has been ported to many operating systems, including MS-DOS, Microsoft Windows, VAX/VMS, Atari ST, AmigaOS and various Unix-like operating systems.
Variants of MicroEMACS also exist, such as MicroGNUEmacs (later renamed mg), a more GNU Emacs-compatible editor. Many relationships to vi can also be found in MicroEMACS. The vi clone vile was based on an older version of MicroEMACS.
Linus Torvalds uses a customized version (maintained by him) of uEmacs/PK 4.0.15. This version was adapted by Petri H. Kutvonen from MicroEMACS 3.9e.