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Multics (Multiplexed Information and Computing Service) is a mainframe timesharing operating system begun in 1965 and used until 2000. Multics began as a research project and was an important influence on operating system development. The system became a commercial product sold by Honeywell to education, government, and industry. This web site describes the hardware, software, and people that made the system the best thing of its kind for many years.

Professor Corbató sent a letter to all Multicians on the occasion of the last system's shutdown on 10/31/2000.

new  Multics is now open source. Source for MR 12.5 is now 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. (11/09/07)

General Information and FAQ

General information about Multics and info on other on-line resources. (42K, 11/15/07)

Multicians

People who contributed to Multics, with home page and mail links. 1915 names, 679 mail addresses, 141 home pages. (508K, 04/23/08) Add or update your entry.

Features

More detail on features of Multics. (62K, 02/29/08, 3 pictures)

History

The history of Multics, from 1963 to 2000. (51K, 04/20/08, 4 pictures)

The Multics History Project is scanning and preserving Multics history.

Stories

Stories and reminiscences about Multics history and its builders. (04/02/08, 33K, 32 contributors, 69 stories, 190 pictures, 13 PDFs)

Myths About Multics

There are a lot of incorrect statements about Multics online. This section tries to correct some of them. (57K, 12/13/07)

Execution Environment

The execution environment for Multics programs. (119K, 02/29/08, 13 figures)

Networking and Communications

The evolution of Multics terminal and network communications. (100K, 09/24/07, 2 figures)

PL/I

How Multics was built in a high-level language. Compiler construction and compiler features. (51K, 11/09/06)

Bibliography

References to published and unpublished information on Multics. (269K, 03/20/08, 616 documents, 230 online)

Technical Papers

A selection of technical papers about Multics is available on-line. (20K, 04/12/07, 35 papers)

Chronology

Chronological list of dates in the history of Multics. (45K, 06/20/07)

Glossary

An encyclopedic, cross-referenced dictionary of Multics terms, concepts, and jargon, with contributions by many Multicians. (27 files, 04/19/08, 824 entries)
Index| A| B| C| D| E| F| G| H| I| J| K| L| M| N| O| P| Q| R| S| T| U| V| W| X| Y| Z|

Humor

Jokes about Multics. (32K, 11/20/05, 1 picture)

Memorabilia

A few items we saved. (13K, 01/14/07, 19 pictures)

Development Documents

The documents we produced while building Multics. A few samples from these hundreds of documents are on-line:

• Multics Design Notebook, section I: Introduction by Professor Corbató (13K, 11/30/64, posted 10/10/01)
• AW17: Multics Commands and Active Functions pocket guide (81K, 04/01/80, posted 05/07/99)
• AG91: Multics Programmers' Manual: Reference Guide Table of Contents (170K, 1984, posted 11/28/98)
• Reserved Segment Name Suffixes AG91 Appendix E (8K, 11/24/98)
• Multics System Programmer's Manual (17K, posted 10/07/05, 839 sections, 7 online)
  • BA.1 MSPM- General Information (5K, 07/26/68)
  • BA.2 Summary of Multics Technical Policy (5K, 07/26/65)
  • BA.3.00 Documentation Conventions (8K, 05/19/66)
  • BB.2 System Module Interfaces (PL/I Subset for System Programming) (19K, 9 figures, 6/24/66)
  • BB.2.01 EPL Subset for System Programming (6K, 01/31/69)
  • BB.3.01 Multics Standard Tape Format (9K, 06/02/67)
  • BX.1.00 Multics Command Language (18K, 10/29/68)
• Multics Technical Bulletins Index (234K, 11/05/87, 719 documents)
• MAB-048 Rules for the Multics Change Review Board (20K, 08/12/85)

Program Source

Samples of Multics source code in PL/I and ALM. (9K, 11/20/05, 8 files)
Index to the Multics source files (1297K, 11/10/07, 5839 entries)

Other Web Sites

Links to other Internet sites of interest to Multicians. (35K, 04/24/08)

Image Gallery

A visual index to all the graphic images on the site, linked to where they are used. (348 thumbnails -- high speed connection recommended) (82K, 01/06/08)

Sites

84 sites, 29 with site history. Mouse over a site name for more information.

Site Timeline (36K, 07/13/07). Site listing (37K, 04/16/08).

Usenet News

The newsgroup alt.os.multics is active and discusses Multics features and history, influence on other systems, Multicians, and the usual newsgroup noise.