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| Open SIMH | |
|---|---|
| Developer | Robert M. Supnik |
| Initial release | 1993[1] |
| Stable release | 3.12-3[2]  / 31 January 2023 |
| 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 | opensimh |
| Repository | |
SIMH is afree and open source, multi-platform multi-systememulator. It is maintained by Bob Supnik, a formerDEC engineer and DEC vice president, based on a much older systems emulator called MIMIC.
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 preservingminicomputer hardware and software that was fading into obscurity.[1]
In May 2022, theMIT License of SIMH version 4 onGitHub was unilaterally modified by a contributor to make itno 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 underBSD licenses and the MIT License) wasforked 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.
The V4 GitHub repository has been placed under a modified license that effectively makes it closed source. It will no longer be referenced here.
