Computer Simulation and History

This site documents my work on SimH, a simulator for historic computer systems, as well as papers and reflections on the history of computing, particularly at Digital Equipment Corporation (DEC).

SimH (History Simulator) is a loose Internet-based collective of people interested in restoring historically significant computer hardware and software systems by simulation. The goal of the project is to create highly portable system simulators and to publish them as freeware on the Internet, with freely available copies of significant or representative software. The current, official version of SimH can be found in a GitHub source repository. It includes many additional simulators, as well as more advanced core libraries.

This site reflects my personal development branch (sometimes called "3.X") and (mostly) the simulators I have worked on.


SIMH is a highly portable, multi-system simulator.

SIMH implements simulators for:

The beta kit includes simulators for:

Also available is a collection of tools for manipulating simulator file formats and for cross-assembling code for the PDP-1, PDP-7, PDP-8, and PDP-11.

Software Kits to run on SIMH

Help with SIMH

System Photographs

Papers on Simulation and Historic Hardware

DEC's Microprocessors (through 1992)

Future Work and Items Needed

List of Contributors

Links to Computer History and Simulation Resources

Updated 21-Feb-2018 by Bob Supnik (simh AT trailing-edge DOT com - anti-spam encoded)