Chapter 1

The preface has gotten so long an intertwined that we moved it to the end for the Project Gutenberg Etext of the Jargon file. You can find it by a search for the following line:

#======= THIS IS THE JARGON FILE, VERSION 4.0.0, 24 JUL 1996 =======#

The Jargon Lexicon ******************

= A = =====

:abbrev: /*-breev'/, /*-brev'/ /n./ Common abbreviation for `abbreviation'.

:ABEND: /a'bend/, /*-bend'/ /n./ [ABnormal END] Abnormal termination (of software); {crash}; {lossage}. Derives from an error message on the IBM 360; used jokingly by hackers but seriously mainly by {code grinder}s. Usually capitalized, but may appear as `abend'. Hackers will try to persuade you that ABEND is called `abend' because it is what system operators do to the machine late on Friday when they want to call it a day, and hence is from the German `Abend' = `Evening'.

:accumulator: /n. obs./ 1. Archaic term for a register. On-line use of it as a synonym for `register' is a fairly reliable indication that the user has been around for quite a while and/or that the architecture under discussion is quite old. The term in full is almost never used of microprocessor registers, for example, though symbolic names for arithmetic registers beginning in `A' derive from historical use of the term `accumulator' (and not, actually, from `arithmetic'). Confusingly, though, an `A' register name prefix may also stand for `address', as for example on the Motorola 680x0 family. 2. A register being used for arithmetic or logic (as opposed to addressing or a loop index), especially one being used to accumulate a sum or count of many items. This use is in context of a particular routine or stretch of code. "The FOOBAZ routine uses A3 as an accumulator." 3. One's in-basket (esp. among old-timers who might use sense 1). "You want this reviewed? Sure, just put it in the accumulator." (See {stack}.)

:ACK: /ak/ /interj./ 1. [from the ASCII mnemonic for 0000110] Acknowledge. Used to register one's presence (compare mainstream *Yo!*). An appropriate response to {ping} or {ENQ}. 2. [from the comic strip "Bloom County"] An exclamation of surprised disgust, esp. in "Ack pffft!" Semi-humorous. Generally this sense is not spelled in caps (ACK) and is distinguished by a following exclamation point. 3. Used to politely interrupt someone to tell them you understand their point (see {NAK}). Thus, for example, you might cut off an overly long explanation with "Ack. Ack. Ack. I get it now".

There is also a usage "ACK?" (from sense 1) meaning "Are you there?", often used in email when earlier mail has produced no reply, or during a lull in {talk mode} to see if the person has gone away (the standard humorous response is of course {NAK} (sense 2), i.e., "I'm not here").

:Acme: /n./ The canonical supplier of bizarre, elaborate, and non-functional gadgetry -- where Rube Goldberg and Heath Robinson shop. Describing some X as an "Acme X" either means "This is {insanely great}", or, more likely, "This looks {insanely great} on paper, but in practice it's really easy to shoot yourself in the foot with it." Compare {pistol}.

This term, specially cherished by American hackers and explained here for the benefit of our overseas brethren, comes from the Warner Brothers' series of "Roadrunner" cartoons. In these cartoons, the famished Wile E. Coyote was forever attempting to catch up with, trap, and eat the Roadrunner. His attempts usually involved one or more high-technology Rube Goldberg devices -- rocket jetpacks, catapults, magnetic traps, high-powered slingshots, etc. These were usually delivered in large cardboard boxes, labeled prominently with the Acme name. These devices invariably malfunctioned in violent and improbable ways.

:acolyte: /n. obs./ [TMRC] An {OSU} privileged enough to submit data and programs to a member of the {priesthood}.

:ad-hockery: /ad-hok'*r-ee/ /n./ [Purdue] 1. Gratuitous assumptions made inside certain programs, esp. expert systems, which lead to the appearance of semi-intelligent behavior but are in fact entirely arbitrary. For example, fuzzy-matching of input tokens that might be typing errors against a symbol table can make it look as though a program knows how to spell. 2. Special-case code to cope with some awkward input that would otherwise cause a program to {choke}, presuming normal inputs are dealt with in some cleaner and more regular way. Also called `ad-hackery', `ad-hocity' (/ad-hos'*-tee/), `ad-crockery'. See also {ELIZA effect}.

:Ada:: /n./ A {{Pascal}}-descended language that has been made mandatory for Department of Defense software projects by the Pentagon. Hackers are nearly unanimous in observing that, technically, it is precisely what one might expect given that kind of endorsement by fiat; designed by committee, crockish, difficult to use, and overall a disastrous, multi-billion-dollar boondoggle (one common description is "The PL/I of the 1980s"). Hackers find Ada's exception-handling and inter-process communication features particularly hilarious. Ada Lovelace (the daughter of Lord Byron who became the world's first programmer while cooperating with Charles Babbage on the design of his mechanical computing engines in the mid-1800s) would almost certainly blanch at the use to which her name has latterly been put; the kindest thing that has been said about it is that there is probably a good small language screaming to get out from inside its vast, {elephantine} bulk.

:adger: /aj'r/ /vt./ [UCLA mutant of {nadger}, poss. from the middle name of an infamous {tenured graduate student}] To make a bonehead move with consequences that could have been foreseen with even slight mental effort. E.g., "He started removing files and promptly adgered the whole project". Compare {dumbass attack}.

:admin: /ad-min'/ /n./ Short for `administrator'; very commonly used in speech or on-line to refer to the systems person in charge on a computer. Common constructions on this include `sysadmin' and `site admin' (emphasizing the administrator's role as a site contact for email and news) or `newsadmin' (focusing specifically on news). Compare {postmaster}, {sysop}, {system mangler}.

:ADVENT: /ad'vent/ /n./ The prototypical computer adventure game, first designed by Will Crowther on the {PDP-10} in the mid-1970s as an attempt at computer-refereed fantasy gaming, and expanded into a puzzle-oriented game by Don Woods at Stanford in 1976. Now better known as Adventure, but the {{TOPS-10}} operating system permitted only six-letter filenames. See also {vadding}, {Zork}, and {Infocom}.

This game defined the terse, dryly humorous style since expected in text adventure games, and popularized several tag lines that have become fixtures of hacker-speak: "A huge green fierce snake bars the way!" "I see no X here" (for some noun X). "You are in a maze of twisty little passages, all alike." "You are in a little maze of twisty passages, all different." The `magic words' {xyzzy} and {plugh} also derive from this game.

Crowther, by the way, participated in the exploration of the Mammoth & Flint Ridge cave system; it actually *has* a `Colossal Cave' and a `Bedquilt' as in the game, and the `Y2' that also turns up is cavers' jargon for a map reference to a secondary entrance.

:AFAIK: // /n./ [Usenet] Abbrev. for "As Far As I Know".

:AFJ: // /n./ Written-only abbreviation for "April Fool's Joke". Elaborate April Fool's hoaxes are a long-established tradition on Usenet and Internet; see {kremvax} for an example. In fact, April Fool's Day is the *only* seasonal holiday consistently marked by customary observances on Internet and other hacker networks.

:AI: /A-I/ /n./ Abbreviation for `Artificial Intelligence', so common that the full form is almost never written or spoken among hackers.

:AI-complete: /A-I k*m-pleet'/ /adj./ [MIT, Stanford: by analogy with `NP-complete' (see {NP-})] Used to describe problems or subproblems in AI, to indicate that the solution presupposes a solution to the `strong AI problem' (that is, the synthesis of a human-level intelligence). A problem that is AI-complete is, in other words, just too hard.

Examples of AI-complete problems are `The Vision Problem' (building a system that can see as well as a human) and `The Natural Language Problem' (building a system that can understand and speak a natural language as well as a human). These may appear to be modular, but all attempts so far (1996) to solve them have foundered on the amount of context information and `intelligence' they seem to require. See also {gedanken}.

:AI koans: /A-I koh'anz/ /pl.n./ A series of pastiches of Zen teaching riddles created by Danny Hillis at the MIT AI Lab around various major figures of the Lab's culture (several are included under {AI Koans} in Appendix A). See also {ha ha only serious}, {mu}, and {{hacker humor}}.

:AIDS: /aydz/ /n./ Short for A* Infected Disk Syndrome (`A*' is a {glob} pattern that matches, but is not limited to, Apple or Amiga), this condition is quite often the result of practicing unsafe {SEX}. See {virus}, {worm}, {Trojan horse}, {virgin}.

:AIDX: /ayd'k*z/ /n./ Derogatory term for IBM's perverted version of Unix, AIX, especially for the AIX 3.? used in the IBM RS/6000 series (some hackers think it is funnier just to pronounce "AIX" as "aches"). A victim of the dreaded "hybridism" disease, this attempt to combine the two main currents of the Unix stream ({BSD} and {USG Unix}) became a {monstrosity} to haunt system administrators' dreams. For example, if new accounts are created while many users are logged on, the load average jumps quickly over 20 due to silly implementation of the user databases. For a quite similar disease, compare {HP-SUX}. Also, compare {Macintrash}, {Nominal Semidestructor}, {Open DeathTrap}, {ScumOS}, {sun-stools}.

:airplane rule: /n./ "Complexity increases the possibility of failure; a twin-engine airplane has twice as many engine problems as a single-engine airplane." By analogy, in both software and electronics, the rule that simplicity increases robustness. It is correspondingly argued that the right way to build reliable systems is to put all your eggs in one basket, after making sure that you've built a really *good* basket. See also {KISS Principle}.

:aliasing bug: /n./ A class of subtle programming errors that can arise in code that does dynamic allocation, esp. via `malloc(3)' or equivalent. If several pointers address (`aliases for') a given hunk of storage, it may happen that the storage is freed or reallocated (and thus moved) through one alias and then referenced through another, which may lead to subtle (and possibly intermittent) lossage depending on the state and the allocation history of the malloc {arena}. Avoidable by use of allocation strategies that never alias allocated core, or by use of higher-level languages, such as {LISP}, which employ a garbage collector (see {GC}). Also called a {stale pointer bug}. See also {precedence lossage}, {smash the stack}, {fandango on core}, {memory leak}, {memory smash}, {overrun screw}, {spam}.

Historical note: Though this term is nowadays associated with C programming, it was already in use in a very similar sense in the Algol-60 and FORTRAN communities in the 1960s.

:all-elbows: /adj./ [MS-DOS] Of a TSR (terminate-and-stay-resident) IBM PC program, such as the N pop-up calendar and calculator utilities that circulate on {BBS} systems: unsociable. Used to describe a program that rudely steals the resources that it needs without considering that other TSRs may also be resident. One particularly common form of rudeness is lock-up due to programs fighting over the keyboard interrupt. See {rude}, also {mess-dos}.

:alpha particles: /n./ See {bit rot}.

:alt: /awlt/ 1. /n./ The alt shift key on an IBM PC or {clone} keyboard; see {bucky bits}, sense 2 (though typical PC usage does not simply set the 0200 bit). 2. /n./ The `clover' or `Command' key on a Macintosh; use of this term usually reveals that the speaker hacked PCs before coming to the Mac (see also {feature key}). Some Mac hackers, confusingly, reserve `alt' for the Option key (and it is so labeled on some Mac II keyboards). 3. /n.,obs/. [PDP-10; often capitalized to ALT] Alternate name for the ASCII ESC character (ASCII 0011011), after the keycap labeling on some older terminals; also `altmode' (/awlt'mohd/). This character was almost never pronounced `escape' on an ITS system, in {TECO}, or under TOPS-10 -- always alt, as in "Type alt alt to end a TECO command" or "alt-U onto the system" (for "log onto the [ITS] system"). This usage probably arose because alt is more convenient to say than `escape', especially when followed by another alt or a character (or another alt *and* a character, for that matter). 4. The alt hierarchy on Usenet, the tree of newsgroups created by users without a formal vote and approval procedure. There is a myth, not entirely implausible, that alt is acronymic for "anarchists, lunatics, and terrorists"; but in fact it is simply short for "alternative".

:alt bit: /awlt bit/ [from alternate] /adj./ See {meta bit}.

:altmode: /n./ Syn. {alt} sense 3.

:Aluminum Book: /n./ [MIT] "Common LISP: The Language", by Guy L. Steele Jr. (Digital Press, first edition 1984, second edition 1990). Note that due to a technical screwup some printings of the second edition are actually of a color the author describes succinctly as "yucky green". See also {{book titles}}.

:amoeba: /n./ Humorous term for the Commodore Amiga personal computer.

:amp off: /vt./ [Purdue] To run in {background}. From the Unix shell `&' operator.

:amper: /n./ Common abbreviation for the name of the ampersand (`&', ASCII 0100110) character. See {{ASCII}} for other synonyms.

:angle brackets: /n./ Either of the characters `<' (ASCII 0111100) and `>' (ASCII 0111110) (ASCII less-than or greater-than signs). Typographers in the {Real World} use angle brackets which are either taller and slimmer (the ISO `Bra' and `Ket' characters), or significantly smaller (single or double guillemets) than the less-than and greater-than signs. See {broket}, {{ASCII}}.

:angry fruit salad: /n./ A bad visual-interface design that uses too many colors. (This term derives, of course, from the bizarre day-glo colors found in canned fruit salad.) Too often one sees similar effects from interface designers using color window systems such as {X}; there is a tendency to create displays that are flashy and attention-getting but uncomfortable for long-term use.

:annoybot: /*-noy-bot/ /n./ [IRC] See {robot}.

:ANSI: /an'see/ 1. /n./ [techspeak] The American National Standards Institute. ANSI, along with the International Organization for Standards (ISO), standardized the C programming language (see {K&R}, {Classic C}), and promulgates many other important software standards. 2. /n./ [techspeak] A terminal may be said to be `ANSI' if it meets the ANSI X.364 standard for terminal control. Unfortunately, this standard was both over-complicated and too permissive. It has been retired and replaced by the ECMA-48 standard, which shares both flaws. 3. /n./ [BBS jargon] The set of screen-painting codes that most MS-DOS and Amiga computers accept. This comes from the ANSI.SYS device driver that must be loaded on an MS-DOS computer to view such codes. Unfortunately, neither DOS ANSI nor the BBS ANSIs derived from it exactly match the ANSI X.364 terminal standard. For example, the ESC-[1m code turns on the bold highlight on large machines, but in IBM PC/MS-DOS ANSI, it turns on `intense' (bright) colors. Also, in BBS-land, the term `ANSI' is often used to imply that a particular computer uses or can emulate the IBM high-half character set from MS-DOS. Particular use depends on context. Occasionally, the vanilla ASCII character set is used with the color codes, but on BBSs, ANSI and `IBM characters' tend to go together.

:AOS: 1. /aws/ (East Coast), /ay'os/ (West Coast) /vt. obs./ To increase the amount of something. "AOS the campfire." [based on a PDP-10 increment instruction] Usage: considered silly, and now obsolete. Now largely supplanted by {bump}. See {SOS}. 2. /n./ A {{Multics}}-derived OS supported at one time by Data General. This was pronounced /A-O-S/ or /A-os/. A spoof of the standard AOS system administrator's manual ("How to Load and Generate your AOS System") was created, issued a part number, and circulated as photocopy folklore; it was called "How to Goad and Levitate your CHAOS System". 3. /n./ Algebraic Operating System, in reference to those calculators which use infix instead of postfix (reverse Polish) notation. 4. A {BSD}-like operating system for the IBM RT.

Historical note: AOS in sense 1 was the name of a {PDP-10} instruction that took any memory location in the computer and added 1 to it; AOS meant `Add One and do not Skip'. Why, you may ask, does the `S' stand for `do not Skip' rather than for `Skip'? Ah, here was a beloved piece of PDP-10 folklore. There were eight such instructions: AOSE added 1 and then skipped the next instruction if the result was Equal to zero; AOSG added 1 and then skipped if the result was Greater than 0; AOSN added 1 and then skipped if the result was Not 0; AOSA added 1 and then skipped Always; and so on. Just plain AOS didn't say when to skip, so it never skipped.

For similar reasons, AOJ meant `Add One and do not Jump'. Even more bizarre, SKIP meant `do not SKIP'! If you wanted to skip the next instruction, you had to say `SKIPA'. Likewise, JUMP meant `do not JUMP'; the unconditional form was JUMPA. However, hackers never did this. By some quirk of the 10's design, the {JRST} (Jump and ReSTore flag with no flag specified) was actually faster and so was invariably used. Such were the perverse mysteries of assembler programming.

:app: /ap/ /n./ Short for `application program', as opposed to a systems program. Apps are what systems vendors are forever chasing developers to create for their environments so they can sell more boxes. Hackers tend not to think of the things they themselves run as apps; thus, in hacker parlance the term excludes compilers, program editors, games, and messaging systems, though a user would consider all those to be apps. (Broadly, an app is often a self-contained environment for performing some well-defined task such as `word processing'; hackers tend to prefer more general-purpose tools.) See {killer app}; oppose {tool}, {operating system}.

:arena: [Unix] /n./ The area of memory attached to a process by `brk(2)' and `sbrk(2)' and used by `malloc(3)' as dynamic storage. So named from a `malloc: corrupt arena' message emitted when some early versions detected an impossible value in the free block list. See {overrun screw}, {aliasing bug}, {memory leak}, {memory smash}, {smash the stack}.

:arg: /arg/ /n./ Abbreviation for `argument' (to a function), used so often as to have become a new word (like `piano' from `pianoforte'). "The sine function takes 1 arg, but the arc-tangent function can take either 1 or 2 args." Compare {param}, {parm}, {var}.

:ARMM: /n./ [acronym, `Automated Retroactive Minimal Moderation'] A Usenet robot created by Dick Depew of Munroe Falls, Ohio. ARMM was intended to automatically cancel posts from anonymous-posting sites. Unfortunately, the robot's recognizer for anonymous postings triggered on its own automatically-generated control messages! Transformed by this stroke of programming ineptitude into a monster of Frankensteinian proportions, it broke loose on the night of March 31, 1993 and proceeded to {spam} news.admin.policy with a recursive explosion of over 200 messages.

ARMM's bug produced a recursive {cascade} of messages each of which mechanically added text to the ID and Subject and some other headers of its parent. This produced a flood of messages in which each header took up several screens and each message ID and subject line got longer and longer and longer.

Reactions varied from amusement to outrage. The pathological messages crashed at least one mail system, and upset people paying line charges for their Usenet feeds. One poster described the ARMM debacle as "instant Usenet history" (also establishing the term {despew}), and it has since been widely cited as a cautionary example of the havoc the combination of good intentions and incompetence can wreak on a network. Compare {Great Worm, the}; {sorcerer's apprentice mode}. See also {software laser}, {network meltdown}.

:armor-plated: /n./ Syn. for {bulletproof}.

:asbestos: /adj./ Used as a modifier to anything intended to protect one from {flame}s; also in other highly {flame}-suggestive usages. See, for example, {asbestos longjohns} and {asbestos cork award}.

:asbestos cork award: /n./ Once, long ago at MIT, there was a {flamer} so consistently obnoxious that another hacker designed, had made, and distributed posters announcing that said flamer had been nominated for the `asbestos cork award'. (Any reader in doubt as to the intended application of the cork should consult the etymology under {flame}.) Since then, it is agreed that only a select few have risen to the heights of bombast required to earn this dubious dignity -- but there is no agreement on *which* few.

:asbestos longjohns: /n./ Notional garments donned by {Usenet} posters just before emitting a remark they expect will elicit {flamage}. This is the most common of the {asbestos} coinages. Also `asbestos underwear', `asbestos overcoat', etc.

:ASCII:: /as'kee/ /n./ [acronym: American Standard Code for Information Interchange] The predominant character set encoding of present-day computers. The modern version uses 7 bits for each character, whereas most earlier codes (including an early version of ASCII) used fewer. This change allowed the inclusion of lowercase letters -- a major {win} -- but it did not provide for accented letters or any other letterforms not used in English (such as the German sharp-S or the ae-ligature which is a letter in, for example, Norwegian). It could be worse, though. It could be much worse. See {{EBCDIC}} to understand how.

Computers are much pickier and less flexible about spelling than humans; thus, hackers need to be very precise when talking about characters, and have developed a considerable amount of verbal shorthand for them. Every character has one or more names -- some formal, some concise, some silly. Common jargon names for ASCII characters are collected here. See also individual entries for {bang}, {excl}, {open}, {ques}, {semi}, {shriek}, {splat}, {twiddle}, and {Yu-Shiang Whole Fish}.