An open source collection of emulators for Windows of historical computers, including GRI-909, HP 2116/2100/21MX, IBM 1401/1620/1130/System 3, PDP-1/4/7-11/15/VAX. Also provides software kits, system photographs, and technical papers.
A Java-based simulator which implements the Mic-1 microarchitecture described in Chapter 4 of Andrew S. Tanenbaum, Structured Computer Organization, Fourth Edition. [Open source, GPL]