Glossary of Multics acronyms and terms. Entries byTom Van Vleck ([THVV]) unless noted.

F&T

Restaurant in Kendall Square, Cambridge, whereProject MACMulticians used to go to lunch. Run by theFox and Tishman family. Not to be confused with the F&T Diner next door. Torn down during the late 1980s.

FAMIS

[BWS] Feature of MR11.0. File Access Methods and Integrity Services. it was an early name for the Data Management (DM) version ofMRDS that supportedtransactions and before journalling. Beta tested atFord in 83/84.

[VS] This is a file access method that supports atomic transactions (including commits and rollbacks). It was designed to provide MRDS with transaction capabilities.

FAST

DTSS simulator, with command conventions made more like Multics.DFAST was a more strict simulation of the Dartmouth system. Both used the sameBASIC compiler.

fatal error

A Multicsprocess can terminate for a number of reasons, such as running off the end of itsstack, taking afault in the fault handling mechanisms, or getting an error writing an error message. In such cases, theanswering service prints a message like

Fatal error. Process has terminated. Fault in signaller. New process created.

and simulates anew_proc command for the user.

fault

[BSG] Processor generated exception causing a diversion of control through afault vector, for any reason except aninterrupt.Page faults,segfaults, bad instructions or out-of-bounds references and the like are all common faults. (There is no notion of "failure").

BOS did not take or process any type of faults. WhenNoel Morris made BOStapes self-booting (seeZero Six Dog), though, thecoup d'étape, as it were, was the processor taking a horrible "trouble fault" by executing one of the magic constants on a "Multics Standard Tape" (seeMST) and Noel's code handling it, not unlike the swift whap on the buttocks of a new-born babe. Butfield engineers not savvy to Multics culture were unimpressed that "Multics starts up by taking a fault." (setting the "stop on fault" CPU switches up was part of their S.O.P.)

fault vector

[BSG] Set of 32 instruction pairs in a fixed location specifying CPU handling of the 32 processorfaults. Rather than specifying a location to transfer to, the 600/6000 architecture specified a pair of instructions to be executed out of line inabsolute mode by thecontrol unit, one of whose tasks was "executing pairs of instructions, no matter how obtained." The first instruction was invariablySCU, and the second, "return", because the Multics return instruction also reloaded the condition code register, which in the case of interrupt vectors was ingeniously used to stash the interrupt number!

FDUMP

BOS command that takes acore dump into a diskpartition instead of printing it on the printer. The saved dump can then be analyzed byifd.

Field Engineers

FEs wereHoneywell employees who installed the big iron and fixed it when it broke. They were an incredibly dedicated group of people, who worked long and strange hours, and responded without complaint to panic calls when the machine wouldn't work. They dealt cheerfully with an exotic, undocumented CPU built far away, running software that changed all the time, and kibitzing by a lot of people who provided unhelpful theories and lots of pressure, but not enough recognition.

file

Seesegment.

File manager

Seevfile_.

file map

Data structure that lists disk record addresses for eachpage of asegment. Stored in the segment'sVTOCE.

file system

Multics was the first operating system to introduce a truehierarchical storage system, in which adirectory could contain other directories.

The paper"A General-Purpose File System For Secondary Storage" describes the 1965 design of the file system.

FIM

Fault Interceptor Module. This program is invoked whenever the hardware encounters afault. It manages machine state and calls the appropriate routine.Harlow Frick,Noel Morris, andTom Van Vleck worked on the original version. In later years, there were actually two FIMs,wired_fim andfim, for faults whose handling has to be done in page-locked environment and not. Source code:fim.alm.

finish

[BSG]PL/I condition signalled in aprocess at logout time (by thelogout command) to allow handlers set up earlier to close open PL/I files and the like. This was a fairly late addition, because Multics' file model, avirtual memory view of disk via sharedsegments, is not PL/I's, and there is little need for such handlers. But they can still cause trouble -- seejladdae.

finjan

SeeZARF.

Firehose drum

SeeLibrafile.

FJCC

Fall Joint Computer Conference. There used to be two big AFIPS conferences a year, one in the spring and one in the fall. Multics was first announced at the 1965 FJCC. See"Introduction and Overview of the Multics System".

FL

Function Language. An assembler thatTom Kinhan of GE CISL was working on but that was never made part of the system.

Flag Day

Any software change that is neither forward nor backward compatible. Named after a change to Multics scheduled for June 14, 1966, when the values of the ASCII character set were switched around.

Flexowriter

Typewriter device made by Friden, which could punch paper tape or type the contents of a paper tape. Flexowriters were used on the very first demonstration versions ofCTSS, and were used to prepareMSPM documentation.

Flower

Honeywell machine, planned as a Multics platform in the 1980s. Planned to be a 3-4x faster machine using gate array technology provided by Honeywell's DoD-funded Very High Speed Integrated Circuit (VHSIC) program. This machine was simulated but never built, and the project was canceled in March 1985. Story:"Flower"

flush

Command that causeslots of paging by creating many largesegments and touching thepages. It is used for performance benchmarks and system debugging.

FNP

[MTB-607] Front-end Network Processor. Also called FEP. SeeSFEP.

Multics supported two models of the FNP. TheDatanet 355 (later known as the Datanet 6632) provided the original communications support for 6180 Multics. (645 Multics used theGIOC for communications I/O.) The Datanet 6661 (and its predecessor, the Datanet 6678) were reimplementations of the 355 architecture usingLevel 6 minicomputer technology.

The FNP software supported the following protocols:

• Asynchronous ASCII
• IBM 1050
• IBM 2741
• ARDS
• Honeywell G115
• BISYNC
• Terminet 1200/202 modem
• Honeywell VIP
• X.25 level 2
• IBM 3270
• HASP

Support was also provided for Automatic Calling Units (ACU's) and the COLTS on-line T&D's.

In 1983, the FNP code contained about 40,000 lines of 355MAP code.

[THVV] Article:Multics Communications and Networking.

Ford

Ford Motor Company. Big Multics customer.Ford had Multics twice. In 1974-1975 Multics was used at Ford on a trial basis. It came back in 1978 and was used until 1997. Site history and story:Ford.

format_document

[PWB] (Short name, fdoc.) Primitive Multics text formatting command. Written byPaul Benjamin of HoneywellFSO McLean. It was written during theEOP benchmark when it was determined thatcompose was too slow andrunoff might soon be unsupported.Unbundled product.

format_document_ was the text formatting subroutine derived from fdoc. Written by Paul Benjamin ofPMDC. Used by many Multics commands that had text formatting requirements, such asforum and themail system.Info segment forformat_document command

format_pl1

PL/I indenting program with many features, options, andcontrol arguments.Stan Dunten wroteIND inMAD onCTSS, andTom Van Vleck ported it to Multics asindent. This program had few options and understood only a subset of PL/I.Paul Green created the much more powerful and flexibleformat_pl1, andMonte Davidoff finished it up, fought all theMCR Board battles, and got it installed as a command.Info segment forformat_pl1 command

In addition to being used for "prettifying" programs,format_pl1 became a tool for canonicalizing programs for textual comparison. For better or worse, it also became a tool for eliminating stylistic variation in PL/I code formatting.

FORTRAN

Multics had three fortran compilers. Version 1 FORTRAN was written using POPS byKe Shih at GE/CISL.

[PG] The version 2 compiler was written inPL/I at CISL, and shared a back end code generator with the PL/I compiler.

[RAB] The last Multics Fortran compiler was written at CISL byDavid Levin,Paul Smee, andRichard Barnes.M. Donald MacLaren did a lot of design work for that compiler, designing the non-optimizing IL (Polish) and code generator. I wrote both optimizing and non-optimizing code generators and the optimizer, designing the optimizing IL (quads). David Levin wrote the parser. Paul Smee wrote a converter from non-optimizing IL to optimizing IL that did some semantic processing as well.

forum

(1) Bulletin board system. A descendant of Pat Doherty'scontinuum fromUSGS, rewritten byMike Auerbach,J. Spencer Love,Jeff Schiller, andJay Pattin atMIT asring 3 site code. Renamed from continuum at French insistence because the short name, "con," was obscene slang in French.Unbundled product released in MR 10.0. Paper:"Experiences with an Interactive Electronic Meeting Facility". See alsoxforum

(2) name of theHLSUA user meetings, e.g. Forum XXVI.

frame

As incore frame, or page frame. A 1024-word block of main memory that can either hold apage or be free. The table of core-frames (the CMP, core map, entries CME, or core-map entry) are in theSST.

FRED

ARPANet interface board. SeeABSI.

FSDCT

File System Device Configuration Table. Held file system parameters andvolume maps (until thenew storage system).

FSIM

File System Interface Module.

FSO

Federal Systems Operation. The division ofHoneywell that handled government contracts, sales, etc. Succeeded by HFSI, Inc.

[Allen Grider] Getronics Government Solutions, LLC. was sold by Getronics and became DigitalNet Government Solutions LLC in December 2002. (owned by DigitalNet). This company can trace its roots back to the Federal Systems Division of Honeywell. So the progression is now:

• Federal Systems Division of Honeywell
• Honeywell Federal Systems, Inc. (when Honeywell sold the computer division toBull, but not us)
• HFS, Inc. (when Honeywell finally sold us to Bull)
• Wang
• Getronics Government Solutions, LLC (owned by Getronics)
• DigitalNet Government Solutions, LLC (owned by DigitalNet)

[Ed Langmaid] BAE Systems purchased DigitalNet Government Solutions in November 2004.

FT2

Fault Tag 2, a hardware indirection indicator that causes a specificfault, used in Multics to cause alinkage fault.

FTP

File Transfer Protocol. Moves files between machines on theARPANet.