Developer(s) | Robert M. Supnik |
---|---|
Initial release | 1993[1] |
Stable release | 3.12-3[2]
/ 31 January 2023 |
Repository | |
Written in | C |
Operating system | Windows, Linux, macOS, FreeBSD, OpenBSD, NetBSD, OpenVMS |
Platform | x86, IA-64, PowerPC, SPARC, ARM |
Type | Hardware virtualization |
License | BSD-style licenses |
Website | simh |
SIMH is a free and open source, multi-platform multi-system emulator. It is maintained by Bob Supnik, a former DEC engineer and DEC vice president, and has been in development in one form or another since the 1960s.
SIMH was based on a much older systems emulator called MIMIC, which was written in the late 1960s at Applied Data Research.[1] SIMH was started in 1993 with the purpose of preserving minicomputer hardware and software that was fading into obscurity.[1]
In May 2022, the MIT License of SIMH version 4 on GitHub was unilaterally modified by a contributor to make it no longer free software, by adding a clause that revokes the right to use any subsequent revisions of the software containing their contributions if modifications that "influence the behaviour of the disk access activities" are made.[3] As of 27 May 2022, Supnik no longer endorses version 4 on his official website for SIMH due to these changes, only recognizing the "classic" version 3.x releases.[4]
On 3 June 2022, the last revision of SIMH not subject to this clause (licensed under BSD licenses and the MIT License) was forked by the group Open SIMH, with a new governance model and steering group that includes Supnik and others. The Open SIMH group cited that a "situation" had arisen in the project that compromised its principles.[5]
SIMH emulates hardware from the following companies.