[TUHS] AT&T 3B2/400 Emulator

Seth Morabito web at loomcom.com
Thu Dec 7 05:00:51 AEST 2017

Hello everyone,

A few weeks ago, I merged my work-in-progress AT&T 3B2/400 emulator
into the main SIMH source tree, and I realized that I should mention
it here, where there may be particular interest.

The 3B2 and 3B5 were main porting platforms for AT&T System V Release
3, and when I realized how scarce the equipment has become to find, I
set out to write an emulator for the 3B2. It was rough going at points
due to lack of documentation, but I was able to reverse engineer quite
a bit of the system through reading the SVR3 source code, and of
course strapping my own 3B2/310 to a logic analyzer.

The emulator is fairly complete. It certainly works well as a
standalone, single-user UNIX system. Support for multiple terminals is
coming very soon (as soon as I find the time, that is) so it will soon
be possible to allow multiple users to telnet into virtual terminals,
similar to how the SIMH PDP-11 and VAX emulators work.

For now, information about the emulator lives here:


Best Wishes,

Seth Morabito
web at loomcom.com

More information about the TUHS mailing list