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Multics today

Could a simulator be written for a Multics CPU?

It has been done. You can download an open source simulator for Multics and install it on a Windows, Macintosh, or Linux machine.

Where can I get a Multics account today?

The last Multics site shut down as of 31 Oct 2000.

Jeffrey Johnson's public access Multics site ban.ai provides public access to a simulated Multics system via the Internet.

Where can I see some Multics hardware?

The Computer History Museum in Mountain View, CA, USA has the hardware for the DOCKMASTER system on "permanent loan" from the National Cryptologic Museum. The hardware is not on public view, but you might be able to arrange a tour.

The Living Computer Museum in Seattle, WA, USA has a 6180 maintenance panel connected to a simulated Multics. You can watch the lights blink.

I'd like to see some Multics source. How?

Bull HN has made the entire source of Multics available "for any purpose and without fee" at MIT as of November 2007. Source for a few programs is available at this site, cross-referenced to the Glossary.

Could Multics be ported to a modern micro?

Probably. Several projects were started to try this in the 80s, as described on the Multics History page. None of these projects finished. Porting Multics would be a big job, and the final product would need further development to match the current state of the art. Paul Green says, "I think it would be easier to try 'improving' existing technology than to resurrect Multics itself."

News Events

See Multics History for historical narrative and the Multics Chronology for historical dates.

Feb 2018: Charles Anthony gave a talk on the Multics simulator at the Vintage Computer Festival Pacific Northwest 2018.

December 2014: The Annual Computer Security Applications Conference (ACSAC) 2014 presented a Distinguished Practitioner Keynote Panel titled "Multics: Before, During, After". Olin Sibert moderated: Roger Schell, Tom Van Vleck, and Steve Lipner were the panelists. The panel talked about the 50-year influence of Multics on computer science and on subsequent systems. Olin demonstrated Harry Reed's Multics Simulator.

November 2014: Harry Reed's simulator for the Multics CPU reached a major milestone on Saturday 08 November. The SIMH-based simulator booted Multics MR 12.5, came to operator command level, entered admin mode, created a small PL/I program, compiled and executed it, and shut down. The simulator has also generated a new Multics System Tape boot image, and booted it. A community of Multicians is making bug fixes and extensions to Multics for use with the simulator.

June 2014: Michael Pandolfo has begun the Multics50 Project to prepare for a celebration of the 50th annversary of Multics in 2015 by organizing a volunteer force to

Contact him to participate.

May 2014: MIT held a 50th anniversary celebration of Project MAC/ LCS/ CSAIL in Cambridge, MA on May 28 & 29, 2014. There was also an associated Multicians' reunion event on May 29. A story with photos and links to videos is online.

Dec 2013: Harry Reed's SIMH-based software simulator for the Multics 6180 CPU has progressed to a point where it can run about 30M instruction cycles of the T&D tape.

Mar 2013: Michael Mondy has been working on a Multics CPU simulator for several years. His simulator is able to load a simulated boot tape and run for many instructions before taking a fault in init_empty_root.

Nov 2012: Harry Reed has started a project to create a software simulator for the Multics CPU based on Bob Supnik's SIMH. The purpose of this project is to create an open source simulator reproducing in sufficient detail the function and capabilities of the Honeywell/Bull DPS-8/M processor with the ultimate goal of resurrecting Multics. Harry is interested in finding volunteers to code, debug, document, test, etc. People who understand the workings of the Multics CPU are especially welcome. For information on this project, use the "Wiki" tab on the SourceForge page linked above.

Nov 2007: Open Source for Multics is hosted at MIT, courtesy of Bull HN. It is available "for any purpose and without fee" provided that the copyright notice and historical background are preserved in all copies.

Oct 2000: The Canadian Dept of National Defence machine at MCHQ (Halifax, NS) shut down at 17:08Z on 10/30/00. This is thought to be the last machine running.

Jul 2000: The CGI (formerly Perigon (formerly ACTC)) machine shut down on July 7, 2000.