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

C

In MR12.0 (1986), a C compiler was written for Multics. Documented in Honeywell manual HH07. It conformed to the Unix System V Release 2.0 compiler.

[BSG] Although never an implementation language for Multics, the ultimately ubiquitous C language traces its ancestry toBCPL, which Multics quietly pioneered .

cache

[BSG] (1) In 1974, the6180 acquired an optional CPU cache. Like most else, this Honeywell hardware innovation was not designed with Multics in mind, andabsolute data address was used as the key to the cache. As in all caches, cached data in one CPU becoming stale when the "real" data is modified by another must be addressed, as it were. Multics's extremelymulticious solution, which wonSteve Webber and hardware designerRiley Dobberstein a US Patent and aHoneywell Sweatt Award, was to invent the "cache" bit of anSDW (implicitly inventing the notion of "encacheability of a segment"), which prevents words from shared, writeable segments or those with physical I/O going on (as determined by software) from going into, or being sought in, the CPU cache. The Multics version of the Cache also included a special version of theassociative memory clearing instruction (cam) that scanned it for and invalidated any words belonging to a specified pageframe.Greenberg invented a scheme for keeping writeable user segments encacheable while they are not actually being shared, including coordinating the notions of "shared between CPUs" and "shared between processes".

[THVV] (2) A design pattern for many mechanisms in Multics.Paging could be viewed as maintaining a cache of disk pages in core.Paging device management cached disk pages in the paging device. TheVTOC Buffer Manager cachedVTOCE parts in its own dedicated storage. Many other examples exist. Once we identified a particular facility as using the cache pattern, we could discuss how we managed write-into versus write-through, how stale entries were invalidated, and so on.

CACL

CommonACL. Up to the early 70s, Multicsdirectories had an additional ACL whose contents were effectively appended to that of each segment within it. This was seen as an easy way to manipulate "default access" in a directory. But not only did this render the computation of effective access unduly complex, but it led to surprises when CACLs were changed when segments already existed. Hence, this scheme was replaced byIACLs.

calendar

Multics provides a program to print wall calendars.Source code is available online.

Calgary

University of Calgary. SeeUC.

call bracket

Range ofrings that can call a given segment as agate. If a segment'sring brackets are 0, 0, 5, the call bracket is rings 0 to 5.

call/save/return

The machine language sequences for inter-subroutine call depend on thestack discipline and the subroutinelinkage conventions. These sequences were conceived of asEPLBSA macros byBob Graham. When threaded code was introduced into the version 2 PL/I compiler, these sequences were moved intopl1_operators_ and theALM macros changed to reference an operator segment. Later, a global change was made to stack discipline for efficiency, without requiring any (normal) program to be recompiled.

Cambridge Project

An MIT-Harvard social science data management project. The Cambridge Project was criticized by campus radicals during the Vietnam War days, because it was funded byARPA. Funding for this project and the Overlap project helped pay to keep the IBM 7094 going at IPC when Multics was late in the 1960s and helped Multics stay alive during its infancy. See the History section"TOSS Summer Study."

[John Klensin] The Cambridge Project produced theConsistent System, "the largest application ever built on Multics and the most comprehensive data analysis, modeling and analysis system ever built."

[Wren McMains] Over its eight year life span, during which time it evolved into the Overlap Project, the directors of the Cambridge Project were Douwe B. Yntema, Joseph Markowitz, and Wren McMains.

canonicalization

Multics converts terminal input lines to a standard form, so that lines that appear identical are identical in storage.

card

The645 came with a card reader and punch. We used the reader to bootGECOS and to loadJohn Gintell's program for taking acore dump. Multics was initially designed tobootload fromtape. (A switch on theGIOC/IOM selects whether theBOOT button on theconsole loads tape or cards.) WhenBOS was invented, it was designed to load from card decks (cold load) or to load from disk under control of aone-card loader. See also theZero Six Dog story.

Under normal service operation, the card reader and punch devices are under control of theI/O Daemon, which accepts requests to punch data out inEBCDIC, binary, or7punch formats, and accepts input card decks preceded by control cards that say what user they are for. Cards were rarely used by average users.

Cardiff

Multics site: Cardiff Joint Computing Centre [CJCC] (Cardiff, Wales). 1982-1991. University of Cardiff and the Welsh National School of Medicine.

carry

Originally a daily sneakernet between theProject MAC andIPCCTSS systems at MIT. Then I think we did it between MIT's CTSS and Multics. Then betweenMIT's Multics and Honeywell'sSystem M inPhoenix. There was an author-maintainedenter_carry_request (ecr) command on the MIT Multics machine and System M. But I forget the details.. there was some complication because ofdisk quotas, and what did we do about security?

CCVR

Multics site: Centre de Calcul Vectoriel pour la Recherche, Ecole Polytechnique (Palaiseau, France), near Paris. Front end to a Cray Y-MP. 1983-1990. Shared machine withCIRCE.

CEDIAG

Bull AI group led byJean Rohmer. Centre d'Expertise et de Developpement en Intelligence Artificielle du Groupe. (Groupe stands for Groupe Bull). SeeAI Tools.

CERAM

Multics site: Centre d'Etude et de Recherche des Alpes Maritimes [CERAM], Sophia-Antipolis, France, near Nice. EDP University (System and Business). One-CPU system, shared machine room withINRIA Sophia. 1981-1986.

[Daniel Bois] Its is an offspring of the Nice Chamber of Commerce. This school teaches mainly "the Art of Selling". In turn CERAM has an offspring : CERICS, which deals mainly with Master and PhD in Computer Science. CERICS was really the biggest user of Multics. And also Multics rimes with CERICS, which is nice !!! CERICS was created by CERAM, CNET and Bull. Jacques Stern was doing the opening speech. I was there ...

CICB

Multics site: Centre Interuniversitaire de Calcul de Bretagne, Universite de Rennes (Rennes, France). 1981-1988.

Had 2000 registered users in 1982.

CICG

Multics site: Centre Interuniversitaire de Calcul de Grenoble, Universite de Grenoble [CICG] (Grenoble, France). 1979-1987.

CICL

Multics site: Centre Interuniversitaire de Traitement de l'Information, Universite de Lille (Lille, France)

CICRP

Multics site: Centre Interuniversitaire de Calcul de la Region Parisienne [CICRP] in Faculty of Jussieu, in Paris, France. 1983-1989.

[Dominique Lalot] IN CICRP, we did not want to go to MR12 (memory and cpu performance), I modified the kernel MR11 to install several add-ons from MR12 like TCP/IP and C language. It was OK for C, but TCP/IP froze the kernel one hour later in a buffer mess that I was unable to determine.

CICT

Multics site: Centre Interuniversitaire de Calcul de Toulouse, Universite Paul Sabatier [CICT], (Toulouse, France), Midi-Pyrénées. 1981-1989.

[Philippe Baqué] Multics was the mainframe on our academic computing centre until approx 1987 after this date a CDC NOS/VE but during 2 years more (until 89) the Multics was UP.

CiiHB

SeeBull.

cipher

Multics commandsencode anddecode implement a powerful file-encryption facility that was shipped with the system for years, starting in the early 1970s. The code, contributed by a Multician with considerable expertise in cryptography, consists of a PL/I wrapper and an assembly language guts. The algorithm is some kind of Feistel cipher, similar to IBM's Lucifer algorithm, "but not the same" according to the author. It was probably illegal to ship these commands internationally, but nobody realized it at the time.

CIRCE

Multics site: Centre InterRegional de Calcul Electronique, Centre de la Recherche Nationale Scientifique (Orsay, France), outside Paris. Shared machine withCCVR. 1983-1990.

CIRIL

SeeNancy.

CISL

Cambridge Information Systems Laboratory. Pronounced "sissle." The group at (GE,Honeywell) that participated in the development of the Multics operating system, and led it afterBTL and thenProject MAC dropped out. Originally housed on the 7th floor of 545Tech Square; moved to 575 Tech Square about 1970; moved to the Cambridge Center building in Kendall Square in 1983; when the people were moved to Billerica in 1986 it wasn't called CISL any more. About 60 people worked at CISL.

CISL had its own6180 system (1974-1986); see theCISL site history.

CISLian

[EAR] AMultician who worked at CISL. SeePhoenician.

clock

The original645 shipped with a separate box that was a microsecond realtime clock with the ability to interrupt any CPU. On the6180, the clock moved into theSCU and didn't take up a port. SeeSCAS. The calendar clock value read by therccl instruction is 52 bits (right-justified in the 72-bit AQ register). Story:"Multics Calendar Clock Calculations".

clock algorithm

[BSG] Page-replacement algorithm (PRA) due toCorbató, whose variants and tweaks remained the Multics PRA for the life of the product. The idea is to approximate "least-recently-used" (LRU) (i.e., when a new coreframe is needed, the "least recently used" page should beevicted.) True LRU is computationally expensive to implement, if not impossible, as it potentially requires reshuffling a queue or stack at every page access. The "Clock algorithm" places all thecore frames in a doubly-linked circular list (like a clock face), with a rotating "hand", in whose wake the "most recently used" pages are, and in advance of whom are the "least-recently-used." When a free frame is required and some page has to be evicted, the hand simply sweeps until a page notPHU (recently used) is found. Pages that are PHU have PHU turned off (i.e., are given a "grace lap"),PHU1 turned on (forpre-paging control), and be passed over, thus, as "most recently used". A page not PHU has a write started if one is needed, or is simply evicted to satisfy the demand. Artificial, "premature" eviction of pages (e.g., fordeactivation ofsegments) moves free core frames to the "LRU" region of the list immediately.

CNET

Multics site: Centre National d'Etudes sur les Télécommunications [CNET] (Issy, France), near Paris. 1982-1988.

CNO

Corporate Network Operations.Honeywell site in Minneapolis, MN. 1979-1987.

COBOL

COBOL compiler done at HoneywellBillerica in early 1970s. Shared internal data structures and code generator with the MulticsPL/I compiler.

collection

A Multicsboot tape contains three logical groups ofsegments called collections. Each collection is read in and then run, to bootstrap a more complex environment for loading and executing the next collection.

[BSG]Collection One consists of all segments necessary for the implementation ofpaging including all hardware I/O (GIOC andIOM control) and thePL/I environment. All of its segments arewired except theconfig deck and some other segments that cannotnot be there (and thedeciduous ones paged and wired).

Collection Two consists of all additional segments that are necessary to implement thefile system, e.g.,segment control,directory control, and the like, and all remaining parts of thering 0supervisor. All of these segments are paged, and none are wired. Some aredeciduous.

Collection Three consists of segments, none of which are part of the supervisor and all of which are loaded into the file system, being precisely the amount of non-supervisor software necessary to get a reload going frombackup tapes.

The term "Collection 0" is sometimes used to refer to a set of segments created incore bybootstrap1 dynamically, theDSEG,config deck,Segment Loading Table, and the like, which are not in any sense loaded from tape.

COLTS

Communications OnLine Test System run byTOLTS. SeeAU77,Multics Online Test and Diagnostics Reference Manual.

combined linkage segment

Per-ring segment that contains theLOT, the ring's STATIC data, outbound links (snapped and unsnapped), and entrypoint names.

command

[BSG] Program designed to be invoked by typing its name at a terminal. Multics commands are ordinary user programs, and what is more, ordinary PL/I procedures. Commands and "subroutines" are indistinguishable at the PL/I anddynamic linking levels. Although this reduces the number of search mechanisms, it rarely turned out to be useful, as calling a command as a subroutine or vice-versa, although fully possible and often done in kludges, presents all kinds of UI problems. The proper handling and diagnosis of missing, malformed, or non-string arguments makes the passing of command arguments as actual parameters a poor idea, and the current C "argc/argv" scheme, an outcome of Multics's experience, is one correct solution.

Correct handling of thestar convention andequal convention are not so easy, though, and the seemingly-obvious solution of relegating that task to theshell (or "command processor") is fraught with well-known dangers whose horror stories adorn the landscape ofUnix critiques.

[THVV] SeeMultics Commands and Active Functions for a list of commands.See alsoadditional names.

command language

The Multics command language derives from theCTSS language, with ideas added from BESYS and TRAC. Thelistener reads lines from the input stream and passes them to theshell for execution.

[PG] The Multics command language permits quoting, iteration and command functions ("active functions") with string return values. The string return values can themselves contain quoting, iteration, or more command functions. By default the command processor evaluates the return value, but you can suppress that and use the unevaluated return value. There is no particular limit to the length of a command line, command argument or return value; the[files] active function returns the names of all files matching astar name, for example, which can easily return hundreds of file names. Everything in Multics is case sensitive; Multics permits use of the full upper and lower caseASCII character set.

Multics command names and programming languages use lowercase by convention, but users are free to use uppercase letters in path names, identifiers, user names, etc.

Simple command line example:

rename a.pl1 b.pl1 /* renames branch a.pl1 to b.pl1 */
/* works on files, dirs, or links */

Quoted command line example:

rename "x y z" "x_y_z" /* change spaces to underscores */
/* yes, filenames could have spaces */

Iteration example:

rename (a b c).pl1 (d e f).pl1

expands to:

rename a.pl1 d.pl1
rename b.pl1 e.pl1
rename c.pl1 f.pl1

Active Function example:

copy [home_dir]>Green.abbrev Green.abbrev.save

All of these features can be combined, nested, etc., to produce very complex (and very useful) command lines. To run two commands on the same file, you can say:

(edm pl1) t.pl1

which runs theedm line editor, then thepl1 compiler, on the filet.pl1.

Since Multics was meant to be extensible, you can write your own commands, your own active functions, your own command processor, or even your own"listener" (the top-level program in the process that reads command lines and dispatches them to the command processor). We had environments that simulated Dartmouth BASIC (byBob Frankston) and GCOS time-sharing, to name two.

[THVV] An early implementation of the Multics command language is described inMSPM sectionBX.1.00. Several features described in that section were changed later, such as the support for two different quoting mechanisms.

command level

[AG91] Process state in which lines input from the user's terminal are interpreted by the system as a command (i.e. the line is sent to thecommand processor). A user is at command level when he logs in, when a command completes or encounters an error, or is stopped by issuing the QUIT signal. Command level is normally indicated by aready message.

command processor

Seeshell. Users may call their command processor viacu_$cp.

compare_ascii

Multics command: compares two ASCII files and prints differences.

compose

Multics text formatting command, successor torunoff. Written byEd Wallman ofPMDC. Begun about 1976.Unbundled product.

computer utility

[BSG] A computer, its software, and staff set up to provide 24-hour service for all of a community's information needs, the ancestor of the "Information Highway". Multics was envisioned as quite this, a "Multiplexed Information and Computing Service", to be present, reliable, powerful, and all that is needed as an information resource for a large number of people, all the time. This was radical at the time, when computers were viewed mainly as tools and toys for "scientists". See"Introduction and Overview of the Multics System".

[THVV] John McCarthy proposed the idea of a computer utility in his 1961 lecture, "Time-sharing Computer Systems," in M. Greenberger (ed.). Management and the Computer of the Future, Cambridge, Mass: The MIT Press, 1963, pp. 221-836

See Martin Greenberger's 1964 article "The Computers of Tomorrow".

config deck

[BSG] An array of card images read byBOS and passed to Multicsinitialization, describing the number and sizes of memories, number of processors, peripherals and their channels, etc., as well as the sizes of critical tables (such as theSST) to be created by initialization. Ultimately, BOS acquired the capability of keeping these images on tape or in its own diskpartition, not needing actual cards.

The cards, or card images, were parsed by an interesting BOS routine ("SCAN") first written byStan Dunten, that determined into what to parse a datum (e.g., 4-character string, octal number, decimal number, letter) by looking at the datum itself, storing one-word "parsed" data in one array and "data types" in a parallel array, very much like a LISP reader.

connect

[BSG] Communication signal sent from oneactive device to another. When received by a processor, as polled for thecontrol unit after each instruction pair like an interrupt, a specialfault (connect fault), very much like aninterrupt, is taken. As with interrupts, processors send "connects" to each other through theSCU, the only possible channel. While an interrupt is set in an SCU register and fielded by the first "taker" of all appropriately masked CPUs, a connect fault is routed by the SCU to one, specified processor (or I/O controller), and cannot be masked against (although the recipient'sinhibit bit can postpone it for a short while). Sending a connect to theGIOC orIOM was the way of instructing it to begin executing I/O commands. SeeSCAS.

Multics uses connects for forcing all CPUs to take note ofSDW andPTW invalidation (and clear theirassociative memories and execute a partialcache clear when appropriate), holding CPUs in the air during critical phases ofdynamic reconfiguration, and the like. If my memory serves me well, functions such as system crashing,scheduler preemption, and processor startup switched back and forth between software-generatedinterrupts and connects throughout the '70s.

connect time

The accounting system metered and charged for "time logged in" because data communication equipment and FNP ports were a scarce resource.

connection failure

At segmentactivation time, segment control checks that the unique ID of the segment from thebranch matches the unique ID in theVTOCE and returns an error otherwise.

Consistent System

Social science data manipulation subsystem built by MIT'sCambridge Project, architected byJohn Klensin.

[Wren McMains] The concept was to provide Social Scientists with a tool box of building blocks that they could put together in ways not envisioned when the individual tools were originally developed. (Much like the Multics/Unix concept of building block commands, but using higher level building blocks designed to meet the statistical and analytical needs of the Social Sciences.)

The Consistent System also tried to solve another problem that still exists 30 years later: An application or command script worked just fine when you used it a couple of years ago, but when you go back and try to do the same thing again with new data it no longer works because someone has "improved" the underlying programs. You're not a computer scientist, you just want do your research. You want the computer to work the way you knew and "loved". You want to get your new answer and get away from the damned computer as soon as possible. The theory was that the Consistent System could seamlessly revert to older versions of software upon command. (I'm not convinced it ever worked seamlessly, but the idea is still worth exploring. Things haven't really gotten better, and instead of 100's of frustrated users there are now 100's of millions around the world.)

console

Terminal device hard wired to theIOM and used for system control. The 645 and 6180 used aSelectric mechanism. Besides the keyboard and printer, the console had a panel with theBOOT button and a "speedometer" measured in MIPS.BOS commands such asMULT,DUMP andBOOT were input on the console by the systemoperator.

The operator console was a lot more than just a terminal mechanism. Its pedestal contained a large amount of circuitry that translated the Selectric codes into GEBCD and enabled the console to work in a primitive environment. The support for theBOOT button was also partly in the console. Proposals for later generations of Honeywell hardware wanted to support complex diagnostics built into a programmable console, and one issue was how to initialize and boot the console, so it could boot the system.

continuum

Bulletin board program that ran on Multics in the late 70s. Supported threaded discussions on multiple topics, like "a one-node version of netnews." Written by USGS employee Pat Doherty. Picked up bySite SAMike Auerbach and installed onSystem M to coordinateMRDS changes in response to theEOP procurement. Ancestor offorum.

control argument

An argument that controls how acommand works. For example,ls -long. There are several types of control arguments:

• simple switches, e.g.-long
• control arguments that take modifier values, e.g.cis -pn fred
• control arguments that can appear multiple times

Like command options inUnix, Multics control arguments are individually coded into the program that is affected by them. By convention, Multics control arguments usually have long and abbreviated forms. Also by convention, Multics control arguments need not appear before operand arguments such as filenames: commands customarily took two passes over the argument list, one to determine all control argument settings, and another to process operands.

print test.pl1 -no_header

and

pr -nhe test.pl1

were equivalent. A few commands were exceptions to this convention.

Control Unit

[BSG] That portion of the6180 processor (the parallel component was theControl Frame on the645) responsible for "instruction preparation", i.e., sequencing, fetching, and decoding instructions, including address computation (as expressed by indirection (seeeppbp)),index registers, and the non-segment portions ofpointer registers.

Fetching instructions in double-word pairs, the CU maintains an internal image of its "current instruction," whose address and tag fields it modifies from those of the successive indirect words it fetches. By buffering two instructions, it supports operations that repeat (RPD, 'repeat double') or execute a pair of instructions out of line (XED ('execute double'), or afault vector). TheCU generates memory requests and dispatches them to theport logic (which queues them), giving the latter a "return address" of whichever processor unit (seeAppending Unit,Decimal Unit,Operations Unit) is supposed to deal with that instruction, to which it also passes off the opcode. (Stores are more or less the same, "but different.":)

Although modified for Multics, the basic CU is not Multics-specific, and does not know aboutsegmentation, let alonepaging. It operates more or less identically in Multics as in aGCOS processor: the illusions of segmentation and paging are created by the Appending Unit.

copy switch

Argument tohcs_$initiate that caused a copy of the segment to be initiated instead of the original.

core

Computer memory technology invented by Jay Forrester of MIT in the 1950s and used on theWHIRLWIND computer, and on 1960s computers including the GE-645. Later models of the6180 used solid-state MOS or other RAM technology, but main memory was often called "core" in casual conversation.

Several different manufacturers produced 645 core memory: Lockheed, Fabritek, who else.. I remember runningmemory diagnostics that printed out FABRITEK WCCP PATTERN TEST, WCCP meant "worst case core pattern." There was a problem in 1966 with non-plated sense wires on core planes from some manufacturer, forget who, that for a while caused the 645 to burn out a core assembly a week. They worked fine in Arizona's dry air, but Boston's salty & polluted atmosphere was too much for them.

core metering

Memory usage metering was described byBob Frankston in his undergraduate thesis. The units of memory occupancy, page-milliseconds, are familiarly called "Frankstons." The official name was "memory units," and the accounting software accumulated and charged for them.

cow's stomach

[BSG] The "Coreadd queue" of Release 6.1 and afterward. This creation ofBernie Greenberg's was a solution to the problem of multi-CPU contention on the "page table lock" (PTL), a "spinlock" on the entirepaging database, which had become a severe performance bottleneck. By the nature of the beast (seewired), disk interrupts, as they arrived atpage control's interrupt side from the diskDIMs, had to spin on this lock, too. The "Cow's stomach" was a queue where the interrupt side saved the results of completed disk operations for later digestion by page control, viz., when the PTL was unlocked.

The algorithm defining the interaction of manipulating this queue with the locking and unlocking of the PTL was quite complex, and took Greenberg some time and effort to devise; when he had done so, he posted outside his doora hand-drawn flowchart replete with starfish and keyhole shapes and other innovations to symbolize non-traditional flowchart steps. The overall shape of a delimited loop representing area protected by a new lock resembled a stomach, and the complexity made many people ask if it was "a cow's stomach." As is evident, the functionality of the thing very much resembled that of a ruminant's stomach-complex, and the name stuck, and was even used for a similar mechanism in later operating systems of other vendors.

CP-6

Honeywell bought rights to the CP-V operating system from Xerox, who had acquired its ancestors from Scientific Data Systems. The port of CP-V to the Honeywell 6000 lineGCOS machines was called CP-6. It was an elegant and capable time-sharing system, programmed in the PL-6 language. Like Multics, CP-6 eventually lost the battle for resources and respect withinLISD. See"The Palyn Report"

CP/CMS

IBM operating system for the 360/67, begun at the IBM Cambridge Scientific Center in Tech Square in the mid-60s. Ancestor of VM. Story: "CP/CMS and the 360/67".

CPU

Central Processing Unit, or processor. Theactive device that fetched machine instructions from memory and executed them. There were two CPU architectures for Multics:645 and6180.

crash

[AG91] An unplanned termination of system availability caused by problems in hardware and/or software.

crawlout

When asignal is raised in an innerring routine called from an outer ring, the signal is reflected back to the caller via a crawlout. To the user process, it appears that the signal originated from a stack frame in the outer ring. Ring 0 takes a special action on crawlouts: if anydirectories arelocked, they are unlocked andsalvaged before leavingring 0.

Cray Station

[BWS] Usually titled Multics Cray Station (although the acronym MCS was already taken). Written byWarren Johnson for CCVR, it made Multics look like anRJE station for a Cray with job, file transfer, and print queues. Used byFord (it was the reason for obtaining the third Multics system),CCVR, and RAE in the UK.

[VS] Ford's original Cray XMP ran COS (Cray Operating System) and required a front-end computer to submit, control, and retrieve jobs. The Cray station software on Multics allowed us to use Multics as a front-end computer for the Cray.

[PWB] Story:The User Ring (see page 2).

Credit Lyonnais

Multics site: Credit Lyonnais (Paris, France). Multics was an InfoCenter, alone, in middle of "IBM only" shop.

CRF

Camelback Road Facility. Honeywell building inPhoenix Phoenix AZ at the corner of Camelback Road and the Black Canyon Freeway that housedPMDC, home of thePhoenicians andSystem M. This building was a former discount store; in 1978 it was painted bright blue.

CS

seeConsistent System.

CSC

Computer Sciences Corporation, Moorestown NJ. This contractor installed 4 Multics systems for theUS Naval War Games System.

csort

[BWS] Cygnus Sort, a more performant reimplementation of the standard Multics sort/merge product by Cygnus Cybernetics Corp (Jim Homan).

CST

[EAR] Copious Spare Time (CST). Personal time spent developing great ideas. e.g. "I developed it in my Copious Spare Time which seemed to be when a lot of stuff got done atCISL."

CTSS

Compatible Time Sharing System. ThisIBM 7094 time-sharing operating system was created at MITProject MAC and first demonstrated in 1961. It was used as the programming and debugging tool during initial Multics programming and bringup by Project MAC, GECISL, andBTL personnel. In some sense the intellectual offspring of CTSS, Multics was conceived as the next step into the future of multiple-access computing. Many of the MIT Multics principals had worked on the earlier system. Story: "The IBM 7094 and CTSS"

CU

SeeControl Unit.

cu_

[BSG] For "command utility". A set of user-ring APIs for accessing command argument lists, supplying user substitutes for and calling thelistener andcommand processor and other functions often needed bycommands.

CUESTA

Simulated user driver for benchmarks. CUESTA could simulate multiple users issuing commands specified by scripts, with varying "think times."

CURSES

Implementation of Unix CURSES package. Added to Multics in the mid 80s.