The Multics development team produced many different series of documents describing Multics and our plans and progress in building it, beginning in the mid 1960s and ending when the system was cancelled in mid 1980. Some documents are available on this site:

Sections describing the development document series follow.

Multics Design Notebook

The very early plans for Multics were described in a set of Project MAC memos called the Multics Design Notebook. These memos were written in 1964 and circulated to the system builders and to other OS researchers to explain what MIT wanted from its next machine. In Section I: Introduction Prof. Corbató mentions that the choice of GE as the system vendor had already been made as of November 64. Most MDN sections were written by MIT Project MAC personnel: there are a few sections by Bell Labs and GE personnel. 27 sections have been scanned by The Multics History Project (MHP) and a scanned online copy of the MDN is on Prof. Saltzer's web site.

The Multics System Programmers' Manual (MSPM)

manuals in a case

The Multics System Programmers' Manual was intended to be the primary design document for Multics. Most of the MSPM was written between 1965 and 1969. The MSPM has been scanned by MHP. The Table of Contents and 822 of the 838 sections are on this site.

Multics Programmer's Manual

The Multics Programmers' Manual (MPM) was begun at Project MAC in 1965 as the follow-on manual to the CTSS User's Guide. As described below, these manuals were taken over by Honeywell, and assigned Honeywell document numbers.

Repository Documents

During the early development phase of the project, 1965 to 1968, there were a number of other documents that didn't fit into the MSPM. Technical white papers, tool documentation, and so forth were assigned a "repository number" and published to the project. There were three series: M for MIT Project MAC, B for Bell Labs, and G for General Electric. There were about 100 documents in each series, but the online table does not list those that were later obsoleted. A few of these documents are available online.

Multics Planning Notebook

The Multics Planning Notebook (MPN) was a multi-section management document which described Multics production milestones and tasks in the 1967-69 time frame. These memos have been scanned by MHP but are not available online.

Checkout Bulletins and Related Documents

Multics Checkout Bulletins (MCBs), and their successors Multics Technical Bulletins (MTBs), were design documents created by the development staff proposing, explaining, and expanding ideas for changes to Multics. As described in "The Multics System Programming Process," one or more MCBs would be written as the first step in introducing a significant change to the system. MCB numbers started at 1 and went up to 1130, before the series was replaced in 1978 by MTBs (because Multics "checkout" was finished). A partial Multics Checkout Bulletins Index is available online. (Jerry Saltzer preserved a few of these.)

The MTB series began in 1973 and continued on into the 1980s. (An index of 732 MTBs from 1973 to 1987 (245K, 07/16/24) is available online.) At first, MCBs also covered task assignments and schedules, but later these kinds of documents were put into a different series, Multics Task Reports (MTRs) from 1973-1983. Some of these memos have been scanned by MHP but are not available online.

After the release of the Multics Simulator in 2015, changes to Multics were proposed and documented in MTBs, listed in Post-Honeywell MTBs, MTBs since 2015.

Project MAC's Computer Systems Research Group produced a series of 55 Multics Performance Log (MPL) memos from 1969-1971. GE personnel wrote several of these. (MHP has these.)

A series of memos were written about 1970 describing the proposed system design of the "follow-on" machine to the 645. This machine eventually became the Honeywell 6180. The series was called Multics Hardware Design Memos (MHDM). MHDM-12 by Corby was the one cited in the MIT/GE agreements.

In 1971-73 Multics Staff Bulletins (MSBs) were produced: they began as a set of memos listing tasks to be done, and later added technical memos on various system improvements. (MHP scanned these; 82 are online.)

There were also 33 Multics Administrative Bulletins (MABs) describing rules and practices to be followed. (We have 16 online, and MHP has a few more.)

Multics Operating Staff Notes (MOSNs) informed the system operators at MIT of procedural changes; many of these were combined into a Honeywell manual, the Multics Operator's Handbook. (MHP has a few of these from 1970-73.)

Between 1980 and 1983, 17 documents in the Multics Alternative Documentation (MAD) series were produced by and for Multics site analysts.

In order to obtain the B2 Orange Book rating, a set of documents describing the Multics design and security implementation, a series of 27 Multics Design Documents (MDD) was produced.

MIT memos

MIT Project MAC produced many Technical Reports and Technical Memos. MIT theses that were done using MAC facilities were often published as TRs or TMs. The MIT Library 2000 project scanned a large number of these documents and the images and abstracts are available online on a server provided by the MIT Libraries. See the Multics Bibliography for pointers to these documents. (These documents are no longer accessible on the web.)

In 1976-85 the MIT LCS Computer Systems Research group produced 276 CSR-RFC memos: up to about 1977, some of these were about Multics. (MHP has these.)

From 1973-78 a series of 449 Multics Installation Bulletins (MIBs) were produced by the MIT IPC Library Maintenance group. (MHP has the whole series.)

In 1976-84 MIT IPC produced 211 Multics System Status memos (MSS) describing system uptime status and crash analysis. (MHP has these.)

Multics Change Documents

In order to make any change to Multics, even a one-line fix, a programmer had to fill out a Multics Change Request (MCR) and have it approved by the MCR Board. This practice was instituted in 1973, and is documented in "The Multics System Programming Process". The online list of MCRs has not survived, but lists of 1360 approved MCRs from 1973 through 1980 have been saved by MHP, as well as MCR packets and minutes from the Phoenix MCRB from 1980-1987. An incomplete Index of Multics Change Requests covering 1973-1976 is available online.

Once a change request was approved, the programmer filled out a "yellow form," which told the program librarians which source modules to pick up, how to recompile them, and how to integrate them into the operating system. The yellow form required the signatures of the programmer, programmer's manager, auditor, and documentation representative. The MCR and yellow form were replaced by electronic versions in the 1980s, near the end of the system's development. MAB-048 describes the rules for the MCR board as of 1985 and contains a sample MCR form.

After the release of the Multics Simulator in 2015, changes to Multics were proposed and documented in MCRs, listed in Post-Honeywell MCRs, MCRs since 2015.

Multics Trouble Reports

Trouble reports were submitted by Multics site analysts, or generated internally by developers. A trouble report database was maintained and TR state was tracked. No examples seem to have survived.


When Honeywell turned Multics into a commercial product, one of its steps was to take over the MPM and produce it as a four-volume set of standard Honeywell printed manuals,

Honeywell eventually produced almost 140 manuals describing Multics. Many of these manuals have been scanned and put online by Al Kossow at Manual AW17 was a brief summary of commands.

Papers, Books, and Articles

Over conference papers, books, and articles about Multics were written during the system's lifetime, many by members of the development team. There is a separate index page for papers available online.