Install open-simh with Homebrew, Nix, scoop, winget, chocolatey, apt, MacPorts, zypper

Project links

• Homepage
• Repository

Commands and aliases

• altair
• eclipse
• gri
• h316
• i1401
• i1620
• i7094
• id16
• id32
• lgp
• pdp1
• pdp10
• pdp11
• pdp15
• pdp4
• pdp7
• pdp8
• pdp9
• sds
• uc15
• vax
• vax780

Project history

SIMH was initiated by Bob Supnik and continued by many contributors to preserve the knowledge contained in old software by simulating the hardware on which it ran. Supnik's classic SIMH site describes the goal as publishing portable open-source simulators together with representative software for historically significant systems.

A SIMH presentation by Supnik explains that the project began in 1993 after Larry Stewart pointed out that computing's past was being lost. The initial targets were well-documented minicomputers such as the DEC PDP-8, DEC PDP-11, and Data General Nova, with MIMIC from the late 1960s and early 1970s serving as a starting point.

Open SIMH's repository README says its code base was taken from a code base maintained by Mark Pizzolato as of 2022-05-12, after which there was no connection between that source and the Open SIMH code base. The Open SIMH site describes a steering-group model for maintaining the simulators and related tools.

Adoption history

SIMH grew from a one-person hobby into an Internet-enabled preservation project. Supnik's presentation says it moved from one code base to a collaborative effort of more than 30 people and became part of a broader ecosystem of collectors, document archivists, simulator writers, restoration projects, and museums.

Open SIMH serves users who want a maintained, MIT-style licensed V4 simulator family with GitHub-based collaboration. The classic SIMH site notes that the V4 stream contains substantially enhanced code and additional simulators, while classic V3 remains separately maintained.

How it is used

Users run a specific simulator binary, attach disk or tape images, configure memory and devices, and boot historical operating systems or diagnostics. The Homebrew package's many executables mirror that model: each binary represents a historically distinct machine family rather than a single generic emulator front end.

SIMH is used for preservation, education, retrocomputing, and practical replacement of aging systems. Supnik's presentation cites uses beyond hobby work, including PDP-11 operating-system development and replacement VAX platform work in a government software-development setting.

Why package nerds care

Open SIMH is package-nerd rich because it turns a preservation codebase into a pile of executable historical machines. A single formula installs many command names, and the value of the package depends as much on documentation, example software kits, and compatible disk/tape image formats as on the compiled binaries.

It also illustrates a rare packaging concern: software preservation packages may care less about speed or modern UI and more about faithful enough behavior to boot old operating systems and expose decades-old assumptions.

Timeline

• 1993: Supnik began SIMH after being prompted to help preserve computing history.
• 1996: Supnik's presentation reports six simulators and two host platforms at that stage.
• 2004-era presentation snapshot: SIMH had grown to more than two dozen simulated machines and many host platforms.
• 2022-05-12: the Open SIMH README identifies the code base point from which Open SIMH was taken.
• 2024-07-16: the classic SIMH site lists SIMH V3.12-5 as updated on this date.

Related projects

• Classic SIMH is the 3.x stream maintained on Supnik's trailing-edge.com site.
• MIMIC is the older late-1960s and early-1970s simulation system that Supnik names as a starting point.
• Hercules, MAME, and CyberCray appear in Supnik's computer-history ecosystem discussion as neighboring simulator projects.

Sources

• https://formulae.brew.sh/formula/open-simh
• https://github.com/open-simh/simh
• https://opensimh.org/
• https://opensimh.org/about/
• https://simh.trailing-edge.com/
• https://simh.trailing-edge.com/docs/simh_vcf.pdf