:death code: n. A routine whose job is to set everything in the computer —- registers, memory, flags, everything —- to zero, including that portion of memory where it is running; its last act is to stomp on its own "store zero" instruction. Death code isn't very useful, but writing it is an interesting hacking challenge on architectures where the instruction set makes it possible, such as the PDP-8 (it has also been done on the DG Nova). Death code is much less common, and more anti-social, on modern multi-user machines. It was very impressive on earlier hardware that provided front panel switches and displays to show register and memory contents, esp. when these were used to prod the corpse to see why it died.

Perhaps the ultimate death code is on the TI 990 series, where all registers are actually in RAM, and the instruction "store immediate 0" has the opcode "0". The PC will immediately wrap around core as many times as it can until a user hits HALT. Any empty memory location is death code. Worse, the manufacturer recommended use of this instruction in startup code (which would be in ROM and therefore survive).

:Death Star: [from the movie "Star Wars"] 1. The AT&T corporate logo, which appears on computers sold by AT&T and bears an uncanny resemblance to the 'Death Star' in the movie. This usage is particularly common among partisans of {BSD} UNIX, who tend to regard the AT&T versions as inferior and AT&T as a bad guy. Copies still circulate of a poster printed by Mt. Xinu showing a starscape with a space fighter labeled 4.2 BSD streaking away from a broken AT&T logo wreathed in flames. 2. AT&T's internal magazine, 'Focus', uses 'death star' for an incorrectly done AT&T logo in which the inner circle in the top left is dark instead of light —- a frequent result of dark-on-light logo images.

:DEC Wars: n. A 1983 {USENET} posting by Alan Hastings and Steve Tarr spoofing the "Star Wars" movies in hackish terms. Some years later, ESR (disappointed by Hastings and Tarr's failure to exploit a great premise more thoroughly) posted a 3-times-longer complete rewrite called "UNIX WARS"; the two are often confused.

:DEChead: /dek'hed/ n. 1. A DEC {field servoid}. Not flattering. 2. [from 'deadhead'] A Grateful Dead fan working at DEC.

:deckle: /dek'l/ [from dec- and {nybble}; the original spelling seems to have been 'decle'] n. Two {nickle}s; 10 bits. Reported among developers for Mattel's GI 1600 (the Intellivision games processor), a chip with 16-bit-wide RAM but 10-bit-wide ROM.

:deep hack mode: n. See {hack mode}.

:deep magic: [poss. from C. S. Lewis's "Narnia" books] n. An awesomely arcane technique central to a program or system, esp. one not generally published and available to hackers at large (compare {black art}); one that could only have been composed by a true {wizard}. Compiler optimization techniques and many aspects of {OS} design used to be {deep magic}; many techniques in cryptography, signal processing, graphics, and AI still are. Compare {heavy wizardry}. Esp. found in comments of the form "Deep magic begins here...". Compare {voodoo programming}.

:deep space: n. 1. Describes the notional location of any program that has gone {off the trolley}. Esp. used of programs that just sit there silently grinding long after either failure or some output is expected. "Uh oh. I should have gotten a prompt ten seconds ago. The program's in deep space somewhere." Compare {buzz}, {catatonic}, {hyperspace}. 2. The metaphorical location of a human so dazed and/or confused or caught up in some esoteric form of {bogosity} that he or she no longer responds coherently to normal communication. Compare {page out}.

:defenestration: [from the traditional Czechoslovak method of assassinating prime ministers, via SF fandom] n. 1. Proper karmic retribution for an incorrigible punster. "Oh, ghod, that was *awful*!" "Quick! Defenestrate him!" 2. The act of exiting a window system in order to get better response time from a full-screen program. This comes from the dictionary meaning of 'defenestrate', which is to throw something out a window. 3. The act of discarding something under the assumption that it will improve matters. "I don't have any disk space left." "Well, why don't you defenestrate that 100 megs worth of old core dumps?" 4. [proposed] The requirement to support a command-line interface. "It has to run on a VT100." "Curses! I've been defenestrated!"

:defined as: adj. In the role of, usually in an organization-chart sense. "Pete is currently defined as bug prioritizer." Compare {logical}.

:dehose: /dee-hohz/ vt. To clear a {hosed} condition.

:delint: /dee-lint/ v. To modify code to remove problems detected when {lint}ing. Confusingly, this is also referred to as 'linting' code.

:delta: n. 1. [techspeak] A quantitative change, especially a small or incremental one (this use is general in physics and engineering). "I just doubled the speed of my program!" "What was the delta on program size?" "About 30 percent." (He doubled the speed of his program, but increased its size by only 30 percent.) 2. [UNIX] A {diff}, especially a {diff} stored under the set of version-control tools called SCCS (Source Code Control System) or RCS (Revision Control System). 3. n. A small quantity, but not as small as {epsilon}. The jargon usage of {delta} and {epsilon} stems from the traditional use of these letters in mathematics for very small numerical quantities, particularly in 'epsilon-delta' proofs in limit theory (as in the differential calculus). The term {delta} is often used, once {epsilon} has been mentioned, to mean a quantity that is slightly bigger than {epsilon} but still very small. "The cost isn't epsilon, but it's delta" means that the cost isn't totally negligible, but it is nevertheless very small. Common constructions include 'within delta of —-', 'within epsilon of —-': that is, close to and even closer to.

:demented: adj. Yet another term of disgust used to describe a program. The connotation in this case is that the program works as designed, but the design is bad. Said, for example, of a program that generates large numbers of meaningless error messages, implying that it is on the brink of imminent collapse. Compare {wonky}, {bozotic}.

:demigod: n. A hacker with years of experience, a national reputation, and a major role in the development of at least one design, tool, or game used by or known to more than half of the hacker community. To qualify as a genuine demigod, the person must recognizably identify with the hacker community and have helped shape it. Major demigods include Ken Thompson and Dennis Ritchie (co-inventors of {{UNIX}} and {C}) and Richard M. Stallman (inventor of {EMACS}). In their hearts of hearts, most hackers dream of someday becoming demigods themselves, and more than one major software project has been driven to completion by the author's veiled hopes of apotheosis. See also {net.god}, {true-hacker}.

:demo: /de'moh/ [short for 'demonstration'] 1. v. To demonstrate a product or prototype. A far more effective way of inducing bugs to manifest than any number of {test} runs, especially when important people are watching. 2. n. The act of demoing. 3. n. Esp. as 'demo version', can refer to either a special version of a program (frequently with some features crippled) which is distributed at little or no cost to the user for demonstration purposes.

:demo mode: [Sun] n. 1. The state of being {heads down} in order to finish code in time for a {demo}, usually due yesterday. 2. A mode in which video games sit there by themselves running through a portion of the game, also known as 'attract mode'. Some serious {app}s have a demo mode they use as a screen saver, or may go through a demo mode on startup (for example, the Microsoft Windows opening screen —- which lets you impress your neighbors without actually having to put up with {Microsloth Windows}).

:demon: n. 1. [MIT] A portion of a program that is not invoked explicitly, but that lies dormant waiting for some condition(s) to occur. See {daemon}. The distinction is that demons are usually processes within a program, while daemons are usually programs running on an operating system. Demons are particularly common in AI programs. For example, a knowledge-manipulation program might implement inference rules as demons. Whenever a new piece of knowledge was added, various demons would activate (which demons depends on the particular piece of data) and would create additional pieces of knowledge by applying their respective inference rules to the original piece. These new pieces could in turn activate more demons as the inferences filtered down through chains of logic. Meanwhile, the main program could continue with whatever its primary task was. 2. [outside MIT] Often used equivalently to {daemon} —- especially in the {{UNIX}} world, where the latter spelling and pronunciation is considered mildly archaic.

:depeditate: /dee-ped'*-tayt/ [by (faulty) analogy with 'decapitate'] vt. Humorously, to cut off the feet of. When one is using some computer-aided typesetting tools, careless placement of text blocks within a page or above a rule can result in chopped-off letter descenders. Such letters are said to have been depeditated.

:deprecated: adj. Said of a program or feature that is considered obsolescent and in the process of being phased out, usually in favor of a specified replacement. Deprecated features can, unfortunately, linger on for many years. This term appears with distressing frequency in standards documents when the committees which write them decide that a sufficient number of users have written code which depends on specific features which are out of favor.

:deserves to lose: adj. Said of someone who willfully does the {Wrong Thing}; humorously, if one uses a feature known to be {marginal}. What is meant is that one deserves the consequences of one's {losing} actions. "Boy, anyone who tries to use {mess-dos} deserves to {lose}!" ({{ITS}} fans used to say this of {{UNIX}}; many still do.) See also {screw}, {chomp}, {bagbiter}.

:desk check: n.,v. To {grovel} over hardcopy of source code, mentally simulating the control flow; a method of catching bugs. No longer common practice in this age of on-screen editing, fast compiles, and sophisticated debuggers —- though some maintain stoutly that it ought to be. Compare {eyeball search}, {vdiff}, {vgrep}.

:Devil Book: n. 'The Design and Implementation of the 4.3BSD UNIX Operating System', by Samuel J. Leffler, Marshall Kirk McKusick, Michael J. Karels, and John S. Quarterman (Addison-Wesley Publishers, 1989) —- the standard reference book on the internals of {BSD} UNIX. So called because the cover has a picture depicting a little devil (a visual play on {daemon}) in sneakers, holding a pitchfork (referring to one of the characteristic features of UNIX, the 'fork(2)' system call).

:devo: /dee'voh/ [orig. in-house jargon at Symbolics] n. A person in a development group. See also {doco} and {mango}.

:dickless workstation: n. Extremely pejorative hackerism for 'diskless workstation', a class of botches including the Sun 3/50 and other machines designed exclusively to network with an expensive central disk server. These combine all the disadvantages of time-sharing with all the disadvantages of distributed personal computers; typically, they cannot even {boot} themselves without help (in the form of some kind of {breath-of-life packet}) from the server.

:dictionary flame: [USENET] n. An attempt to sidetrack a debate away from issues by insisting on meanings for key terms that presuppose a desired conclusion or smuggle in an implicit premise. A common tactic of people who prefer argument over definitions to disputes about reality.

:diddle: 1. vt. To work with or modify in a not particularly serious manner. "I diddled a copy of {ADVENT} so it didn't double-space all the time." "Let's diddle this piece of code and see if the problem goes away." See {tweak} and {twiddle}. 2. n. The action or result of diddling. See also {tweak}, {twiddle}, {frob}.

:die: v. Syn. {crash}. Unlike {crash}, which is used primarily of hardware, this verb is used of both hardware and software. See also {go flatline}, {casters-up mode}.

:die horribly: v. The software equivalent of {crash and burn}, and the preferred emphatic form of {die}. "The converter choked on an FF in its input and died horribly".

:diff: /dif/ n. 1. A change listing, especially giving differences between (and additions to) source code or documents (the term is often used in the plural 'diffs'). "Send me your diffs for the Jargon File!" Compare {vdiff}. 2. Specifically, such a listing produced by the 'diff(1)' command, esp. when used as specification input to the 'patch(1)' utility (which can actually perform the modifications; see {patch}). This is a common method of distributing patches and source updates in the UNIX/C world. See also {vdiff}, {mod}.

:digit: n. An employee of Digital Equipment Corporation. See also {VAX}, {VMS}, {PDP-10}, {{TOPS-10}}, {DEChead}, {double DECkers}, {field circus}.

:dike: vt. To remove or disable a portion of something, as a wire from a computer or a subroutine from a program. A standard slogan is "When in doubt, dike it out". (The implication is that it is usually more effective to attack software problems by reducing complexity than by increasing it.) The word 'dikes' is widely used among mechanics and engineers to mean 'diagonal cutters', esp. a heavy-duty metal-cutting device, but may also refer to a kind of wire-cutters used by electronics techs. To 'dike something out' means to use such cutters to remove something. Indeed, the TMRC Dictionary defined dike as "to attack with dikes". Among hackers this term has been metaphorically extended to informational objects such as sections of code.

:ding: n.,vi. 1. Synonym for {feep}. Usage: rare among hackers, but commoner in the {Real World}. 2. 'dinged': What happens when someone in authority gives you a minor bitching about something, esp. something trivial. "I was dinged for having a messy desk."

:dink: /dink/ n. Said of a machine that has the {bitty box} nature; a machine too small to be worth bothering with —- sometimes the system you're currently forced to work on. First heard from an MIT hacker working on a CP/M system with 64K, in reference to any 6502 system, then from fans of 32-bit architectures about 16-bit machines. "GNUMACS will never work on that dink machine." Probably derived from mainstream 'dinky', which isn't sufficiently pejorative.

:dinosaur: n. 1. Any hardware requiring raised flooring and special power. Used especially of old minis and mainframes, in contrast with newer microprocessor-based machines. In a famous quote from the 1988 UNIX EXPO, Bill Joy compared the mainframe in the massive IBM display with a grazing dinosaur "with a truck outside pumping its bodily fluids through it". IBM was not amused. Compare {big iron}; see also {mainframe}. 2. [IBM] A very conservative user; a {zipperhead}.

:dinosaur pen: n. A traditional {mainframe} computer room complete with raised flooring, special power, its own ultra-heavy-duty air conditioning, and a side order of Halon fire extinguishers. See {boa}.

:dinosaurs mating: n. Said to occur when yet another {big iron} merger or buyout occurs; reflects a perception by hackers that these signal another stage in the long, slow dying of the {mainframe} industry. In its glory days of the 1960s, it was 'IBM and the Seven Dwarves': Burroughs, Control Data, General Electric, Honeywell, NCR, RCA, and Univac. RCA and GE sold out early, and it was 'IBM and the Bunch' (Burroughs, Univac, NCR, Control Data, and Honeywell) for a while. Honeywell was bought out by Bull; Burroughs merged with Univac to form Unisys (in 1984 —- this was when the phrase 'dinosaurs mating' was coined); and as this is written (early 1991) AT&T is attempting to recover from a disastrously bad first six years in the hardware industry by absorbing NCR. More such earth-shaking unions of doomed giants seem inevitable.

:dirtball: [XEROX PARC] n. A small, perhaps struggling outsider; not in the major or even the minor leagues. For example, "Xerox is not a dirtball company".

[Outsiders often observe in the PARC culture an institutional arrogance which usage of this term exemplifies. The brilliance and scope of PARC's contributions to computer science have been such that this superior attitude is not much resented. —- ESR]

:dirty power: n. Electrical mains voltage that is unfriendly to the delicate innards of computers. Spikes, {drop-outs}, average voltage significantly higher or lower than nominal, or just plain noise can all cause problems of varying subtlety and severity (these are collectively known as {power hit}s).

:disclaimer: n. [USENET] n. Statement ritually appended to many USENET postings (sometimes automatically, by the posting software) reiterating the fact (which should be obvious, but is easily forgotten) that the article reflects its author's opinions and not necessarily those of the organization running the machine through which the article entered the network.

:Discordianism: /dis-kor'di-*n-ism/ n. The veneration of {Eris}, a.k.a. Discordia; widely popular among hackers. Discordianism was popularized by Robert Shea and Robert Anton Wilson's '{Illuminatus!}' trilogy as a sort of self-subverting Dada-Zen for Westerners —- it should on no account be taken seriously but is far more serious than most jokes. Consider, for example, the Fifth Commandment of the Pentabarf, from 'Principia Discordia': "A Discordian is Prohibited of Believing What he Reads." Discordianism is usually connected with an elaborate conspiracy theory/joke involving millennia-long warfare between the anarcho-surrealist partisans of Eris and a malevolent, authoritarian secret society called the Illuminati. See {Religion} under {appendix B}, {Church of the SubGenius}, and {ha ha only serious}.

:disk farm: n. (also {laundromat}) A large room or rooms filled with disk drives (esp. {washing machine}s).

:display hack: n. A program with the same approximate purpose as a kaleidoscope: to make pretty pictures. Famous display hacks include {munching squares}, {smoking clover}, the BSD UNIX 'rain(6)' program, 'worms(6)' on miscellaneous UNIXes, and the {X} 'kaleid(1)' program. Display hacks can also be implemented without programming by creating text files containing numerous escape sequences for interpretation by a video terminal; one notable example displayed, on any VT100, a Christmas tree with twinkling lights and a toy train circling its base. The {hack value} of a display hack is proportional to the esthetic value of the images times the cleverness of the algorithm divided by the size of the code. Syn. {psychedelicware}.

:Dissociated Press: [play on 'Associated Press'; perhaps inspired by a reference in the 1949 Bugs Bunny cartoon "What's Up, Doc?"] n. An algorithm for transforming any text into potentially humorous garbage even more efficiently than by passing it through a {marketroid}. You start by printing any N consecutive words (or letters) in the text. Then at every step you search for any random occurrence in the original text of the last N words (or letters) already printed and then print the next word or letter. {EMACS} has a handy command for this. Here is a short example of word-based Dissociated Press applied to an earlier version of this Jargon File:

wart: n. A small, crocky {feature} that sticks out of an array (C has no checks for this). This is relatively benign and easy to spot if the phrase is bent so as to be not worth paying attention to the medium in question.

Here is a short example of letter-based Dissociated Press applied to the same source:

window sysIWYG: n. A bit was named aften /bee't*/ prefer to use the other guy's re, especially in every cast a chuckle on neithout getting into useful informash speech makes removing a featuring a move or usage actual abstractionsidered interj. Indeed spectace logic or problem!

A hackish idle pastime is to apply letter-based Dissociated Press to a random body of text and {vgrep} the output in hopes of finding an interesting new word. (In the preceding example, 'window sysIWYG' and 'informash' show some promise.) Iterated applications of Dissociated Press usually yield better results. Similar techniques called 'travesty generators' have been employed with considerable satirical effect to the utterances of USENET flamers; see {pseudo}.

:distribution: n. 1. A software source tree packaged for distribution; but see {kit}. 2. A vague term encompassing mailing lists and USENET newsgroups (but not {BBS} {fora}); any topic-oriented message channel with multiple recipients. 3. An information-space domain (usually loosely correlated with geography) to which propagation of a USENET message is restricted; a much-underutilized feature.

:do protocol: [from network protocol programming] vi. To perform an interaction with somebody or something that follows a clearly defined procedure. For example, "Let's do protocol with the check" at a restaurant means to ask for the check, calculate the tip and everybody's share, collect money from everybody, generate change as necessary, and pay the bill. See {protocol}.

:doc: /dok/ n. Common spoken and written shorthand for 'documentation'. Often used in the plural 'docs' and in the construction 'doc file' (documentation available on-line).

:doco: /do'koh/ [orig. in-house jargon at Symbolics] n. A documentation writer. See also {devo} and {mango}.

:documentation:: n. The multiple kilograms of macerated, pounded, steamed, bleached, and pressed trees that accompany most modern software or hardware products (see also {tree-killer}). Hackers seldom read paper documentation and (too) often resist writing it; they prefer theirs to be terse and on-line. A common comment on this is "You can't {grep} dead trees". See {drool-proof paper}, {verbiage}.

:dodgy: adj. Syn. with {flaky}. Preferred outside the U.S.

:dogcow: /dog'kow/ n. See {Moof}.

:dogwash: /dog'wosh/ [From a quip in the 'urgency' field of a very optional software change request, ca. 1982. It was something like "Urgency: Wash your dog first".] 1. n. A project of minimal priority, undertaken as an escape from more serious work. 2. v. To engage in such a project. Many games and much {freeware} get written this way.

:domainist: /doh-mayn'ist/ adj. 1. Said of an {{Internet address}} (as opposed to a {bang path}) because the part to the right of the '@' specifies a nested series of 'domains'; for example, eric@snark.thyrsus.com specifies the machine called snark in the subdomain called thyrsus within the top-level domain called com. See also {big-endian}, sense 2. 2. Said of a site, mailer, or routing program which knows how to handle domainist addresses. 3. Said of a person (esp. a site admin) who prefers domain addressing, supports a domainist mailer, or prosyletizes for domainist addressing and disdains {bang path}s. This is now (1991) semi-obsolete, as most sites have converted.

:Don't do that, then!: [from an old doctor's office joke about a patient with a trivial complaint] Stock response to a user complaint. "When I type control-S, the whole system comes to a halt for thirty seconds." "Don't do that, then!" (or "So don't do that!"). Compare {RTFM}.

:dongle: /dong'gl/ n. 1. A security or {copy protection} device for commercial microcomputer programs consisting of a serialized EPROM and some drivers in a D-25 connector shell, which must be connected to an I/O port of the computer while the program is run. Programs that use a dongle query the port at startup and at programmed intervals thereafter, and terminate if it does not respond with the dongle's programmed validation code. Thus, users can make as many copies of the program as they want but must pay for each dongle. The idea was clever, but it was initially a failure, as users disliked tying up a serial port this way. Most dongles on the market today (1991) will pass data through the port and monitor for {magic} codes (and combinations of status lines) with minimal if any interference with devices further down the line —- this innovation was necessary to allow daisy-chained dongles for multiple pieces of software. The devices are still not widely used, as the industry has moved away from copy-protection schemes in general. 2. By extension, any physical electronic key or transferrable ID required for a program to function. See {dongle-disk}.

[Note: in early 1992, advertising copy from Rainbow Technologies (a manufacturer of dongles) included a claim that the word derived from "Don Gall", allegedly the inventor of the device. The company's receptionist will cheerfully tell you that the story is a myth invented for the ad copy. Nevertheless, I expect it to haunt my life as a lexicographer for at least the next ten years. —-ESR]

:dongle-disk: /don'gl disk/ n. See {dongle}; a 'dongle-disk' is a floppy disk which is required in order to perform some task. Some contain special coding that allows an application to identify it uniquely, others *are* special code that does something that normally-resident programs don't or can't. (For example, AT&T's "Unix PC" would only come up in {root mode} with a special boot disk.) Also called a 'key disk'.

:donuts: n.obs. A collective noun for any set of memory bits. This is extremely archaic and may no longer be live jargon; it dates from the days of ferrite-{core} memories in which each bit was implemented by a doughnut-shaped magnetic flip-flop.

:doorstop: n. Used to describe equipment that is non-functional and halfway expected to remain so, especially obsolete equipment kept around for political reasons or ostensibly as a backup. "When we get another Wyse-50 in here, that ADM 3 will turn into a doorstop." Compare {boat anchor}.

:dot file: [UNIX] n. A file which is not visible by default to normal directory-browsing tools (on UNIX, files named with a leading dot are, by convention, not normally presented in directory listings). Many programs define one or more dot files in which startup or configuration information may be optionally recorded; a user can customize the program's behavior by creating the appropriate file in the current or home directory. (Therefore, dot files tend to {creep} —- with every nontrivial application program defining at least one, a user's home directory can be filled with scores of dot files, of course without the user's really being aware of it.) See also {rc file}.

:double bucky: adj. Using both the CTRL and META keys. "The command to burn all LEDs is double bucky F."

This term originated on the Stanford extended-ASCII keyboard, and was later taken up by users of the {space-cadet keyboard} at MIT. A typical MIT comment was that the Stanford {bucky bits} (control and meta shifting keys) were nice, but there weren't enough of them; you could type only 512 different characters on a Stanford keyboard. An obvious way to address this was simply to add more shifting keys, and this was eventually done; but a keyboard with that many shifting keys is hard on touch-typists, who don't like to move their hands away from the home position on the keyboard. It was half-seriously suggested that the extra shifting keys be implemented as pedals; typing on such a keyboard would be very much like playing a full pipe organ. This idea is mentioned in a parody of a very fine song by Jeffrey Moss called "Rubber Duckie", which was published in 'The Sesame Street Songbook' (Simon and Schuster 1971, ISBN 0-671-21036-X). These lyrics were written on May 27, 1978, in celebration of the Stanford keyboard:

Double Bucky

Double bucky, you're the one! You make my keyboard lots of fun. Double bucky, an additional bit or two: (Vo-vo-de-o!) Control and meta, side by side, Augmented ASCII, nine bits wide! Double bucky! Half a thousand glyphs, plus a few! Oh, I sure wish that I Had a couple of Bits more! Perhaps a Set of pedals to Make the number of Bits four: Double double bucky! Double bucky, left and right OR'd together, outta sight! Double bucky, I'd like a whole word of Double bucky, I'm happy I heard of Double bucky, I'd like a whole word of you!

—- The Great Quux (with apologies to Jeffrey Moss)

[This, by the way, is an excellent example of computer {filk} —- ESR] See also {meta bit}, {cokebottle}, and {quadruple bucky}.

:double DECkers: n. Used to describe married couples in which both partners work for Digital Equipment Corporation.

:doubled sig: [USENET] n. A {sig block} that has been included twice in a {USENET} article or, less commonly, in an electronic mail message. An article or message with a doubled sig can be caused by improperly configured software. More often, however, it reveals the author's lack of experience in electronic communication. See {BIFF}, {pseudo}.

:down: 1. adj. Not operating. "The up escalator is down" is considered a humorous thing to say, and "The elevator is down" always means "The elevator isn't working" and never refers to what floor the elevator is on. With respect to computers, this usage has passed into the mainstream; the extension to other kinds of machine is still hackish. 2. 'go down' vi. To stop functioning; usually said of the {system}. The message from the {console} that every hacker hates to hear from the operator is "The system will go down in 5 minutes". 3. 'take down', 'bring down' vt. To deactivate purposely, usually for repair work or {PM}. "I'm taking the system down to work on that bug in the tape drive." Occasionally one hears the word 'down' by itself used as a verb in this vt. sense. See {crash}; oppose {up}.

:download: vt. To transfer data or (esp.) code from a larger 'host' system (esp. a {mainframe}) over a digital comm link to a smaller 'client' system, esp. a microcomputer or specialized peripheral. Oppose {upload}.

However, note that ground-to-space communications has its own usage rule for this term. Space-to-earth transmission is always download and the reverse upload regardless of the relative size of the computers involved. So far the in-space machines have invariably been smaller; thus the upload/download distinction has been reversed from its usual sense.

:DP: /D-P/ n. 1. Data Processing. Listed here because, according to hackers, use of the term marks one immediately as a {suit}. See {DPer}. 2. Common abbrev for {Dissociated Press}.

:DPB: /d*-pib'/ [from the PDP-10 instruction set] vt. To plop something down in the middle. Usage: silly. "DPB yourself into that couch there." The connotation would be that the couch is full except for one slot just big enough for you to sit in. DPB means 'DePosit Byte', and was the name of a PDP-10 instruction that inserts some bits into the middle of some other bits. This usage has been kept alive by the Common LISP function of the same name.

:DPer: /dee-pee-er/ n. Data Processor. Hackers are absolutely amazed that {suit}s use this term self-referentially. "*Computers* process data, not people!" See {DP}.

:dragon: n. [MIT] A program similar to a {daemon}, except that it is not invoked at all, but is instead used by the system to perform various secondary tasks. A typical example would be an accounting program, which keeps track of who is logged in, accumulates load-average statistics, etc. Under ITS, many terminals displayed a list of people logged in, where they were, what they were running, etc., along with some random picture (such as a unicorn, Snoopy, or the Enterprise), which was generated by the 'name dragon'. Usage: rare outside MIT —- under UNIX and most other OSes this would be called a 'background demon' or {daemon}. The best-known UNIX example of a dragon is 'cron(1)'. At SAIL, they called this sort of thing a 'phantom'.

:Dragon Book: n. The classic text 'Compilers: Principles, Techniques and Tools', by Alfred V. Aho, Ravi Sethi, and Jeffrey D. Ullman (Addison-Wesley 1986; ISBN 0-201-10088-6), so called because of the cover design featuring a dragon labeled 'complexity of compiler design' and a knight bearing the lance 'LALR parser generator' among his other trappings. This one is more specifically known as the 'Red Dragon Book' (1986); an earlier edition, sans Sethi and titled 'Principles Of Compiler Design' (Alfred V. Aho and Jeffrey D. Ullman; Addison-Wesley, 1977; ISBN 0-201-00022-9), was the 'Green Dragon Book' (1977). (Also 'New Dragon Book', 'Old Dragon Book'.) The horsed knight and the Green Dragon were warily eying each other at a distance; now the knight is typing (wearing gauntlets!) at a terminal showing a video-game representation of the Red Dragon's head while the rest of the beast extends back in normal space. See also {{book titles}}.

:drain: [IBM] v. Syn. for {flush} (sense 2). Has a connotation of finality about it; one speaks of draining a device before taking it offline.

:dread high-bit disease: n. A condition endemic to PRIME (a.k.a. PR1ME) minicomputers that results in all the characters having their high (0x80) bit ON rather than OFF. This of course makes transporting files to other systems much more difficult, not to mention talking to true 8-bit devices. Folklore had it that PRIME adopted the reversed-8-bit convention in order to save 25 cents per serial line per machine; PRIME old-timers, on the other hand, claim they inherited the disease from Honeywell via customer NASA's compatibility requirements and struggled manfully to cure it. Whoever was responsible, this probably qualifies as one of the most {cretinous} design tradeoffs ever made. See {meta bit}. A few other machines have exhibited similar brain damage.

:DRECNET: /drek'net/ [from Yiddish/German 'dreck', meaning dirt] n. Deliberate distortion of DECNET, a networking protocol used in the {VMS} community. So called because DEC helped write the Ethernet specification and then (either stupidly or as a malignant customer-control tactic) violated that spec in the design of DRECNET in a way that made it incompatible. See also {connector conspiracy}.

:driver: n. 1. The {main loop} of an event-processing program; the code that gets commands and dispatches them for execution. 2. [techspeak] In 'device driver', code designed to handle a particular peripheral device such as a magnetic disk or tape unit. 3. In the TeX world and the computerized typesetting world in general, 'driver' also means a program that translates some device-independent or other common format to something a real device can actually understand.

:droid: n. A person (esp. a low-level bureaucrat or service-business employee) exhibiting most of the following characteristics: (a) na"ive trust in the wisdom of the parent organization or 'the system'; (b) a propensity to believe obvious nonsense emitted by authority figures (or computers!); blind faith; (c) a rule-governed mentality, one unwilling or unable to look beyond the 'letter of the law' in exceptional situations; and (d) no interest in fixing that which is broken; an "It's not my job, man" attitude.

Typical droid positions include supermarket checkout assistant and bank clerk; the syndrome is also endemic in low-level government employees. The implication is that the rules and official procedures constitute software that the droid is executing. This becomes a problem when the software has not been properly debugged. The term 'droid mentality' is also used to describe the mindset behind this behavior. Compare {suit}, {marketroid}; see {-oid}.

:drool-proof paper: n. Documentation that has been obsessively {dumbed down}, to the point where only a {cretin} could bear to read it, is said to have succumbed to the 'drool-proof paper syndrome' or to have been 'written on drool-proof paper'. For example, this is an actual quote from Apple's LaserWriter manual: "Do not expose your LaserWriter to open fire or flame."

:drop on the floor: vt. To react to an error condition by silently discarding messages or other valuable data. "The gateway ran out of memory, so it just started dropping packets on the floor." Also frequently used of faulty mail and netnews relay sites that lose messages. See also {black hole}, {bit bucket}.

:drop-ins: [prob. by analogy with {drop-outs}] n. Spurious characters appearing on a terminal or console as a result of line noise or a system malfunction of some sort. Esp. used when these are interspersed with one's own typed input. Compare {drop-outs}.

:drop-outs: n. 1. A variety of 'power glitch' (see {glitch}); momentary 0 voltage on the electrical mains. 2. Missing characters in typed input due to software malfunction or system saturation (this can happen under UNIX when a bad connection to a modem swamps the processor with spurious character interrupts). 3. Mental glitches; used as a way of describing those occasions when the mind just seems to shut down for a couple of beats. See {glitch}, {fried}.

:drugged: adj. (also 'on drugs') 1. Conspicuously stupid, heading toward {brain-damaged}. Often accompanied by a pantomime of toking a joint (but see {appendix B}). 2. Of hardware, very slow relative to normal performance.

:drum: adj,n. Ancient techspeak term referring to slow, cylindrical magnetic media which were once state-of-the-art mass-storage devices. Under BSD UNIX the disk partition used for swapping is still called '/dev/drum'; this has led to considerable humor and not a few straight-faced but utterly bogus 'explanations' getting foisted on {newbie}s. See also "{The Story of Mel, a Real Programmer}" in {appendix A}.

:drunk mouse syndrome: (also 'mouse on drugs') n. A malady exhibited by the mouse pointing device of some computers. The typical symptom is for the mouse cursor on the screen to move in random directions and not in sync with the motion of the actual mouse. Can usually be corrected by unplugging the mouse and plugging it back again. Another recommended fix for optical mice is to rotate your mouse pad 90 degrees.

At Xerox PARC in the 1970s, most people kept a can of copier cleaner (isopropyl alcohol) at their desks. When the steel ball on the mouse had picked up enough {cruft} to be unreliable, the mouse was doused in cleaner, which restored it for a while. However, this operation left a fine residue that accelerated the accumulation of cruft, so the dousings became more and more frequent. Finally, the mouse was declared 'alcoholic' and sent to the clinic to be dried out in a CFC ultrasonic bath.

:Duff's device: n. The most dramatic use yet seen of {fall through} in C, invented by Tom Duff when he was at Lucasfilm. Trying to {bum} all the instructions he could out of an inner loop that copied data serially onto an output port, he decided to {unroll} it. He then realized that the unrolled version could be implemented by *interlacing* the structures of a switch and a loop:

register n = (count + 7) / 8; /* count > 0 assumed */

switch (count % 8) { case 0: do { *to = *from+; case 7: *to = *from+; case 6: *to = *from+; case 5: *to = *from+; case 4: *to = *from+; case 3: *to = *from+; case 2: *to = *from+; case 1: *to = *from+; } while (—n > 0); }

Having verified that the device is valid portable C, Duff announced it. C's default {fall through} in case statements has long been its most controversial single feature; Duff observed that "This code forms some sort of argument in that debate, but I'm not sure whether it's for or against."

:dumb terminal: n. A terminal which is one step above a {glass tty}, having a minimally-addressable cursor but no on-screen editing or other features which are claimed by a {smart terminal}. Once upon a time, when glass ttys were common and addressable cursors were something special, what is now called a dumb terminal could pass for a smart terminal.

:dumbass attack: /duhm'as *-tak'/ [Purdue] n. Notional cause of a novice's mistake made by the experienced, especially one made while running as {root} under UNIX, e.g., typing 'rm -r *' or 'mkfs' on a mounted file system. Compare {adger}.

:dumbed down: adj. Simplified, with a strong connotation of *over*simplified. Often, a {marketroid} will insist that the interfaces and documentation of software be dumbed down after the designer has burned untold gallons of midnight oil making it smart. This creates friction. See {user-friendly}.

:dump: n. 1. An undigested and voluminous mass of information about a problem or the state of a system, especially one routed to the slowest available output device (compare {core dump}), and most especially one consisting of hex or octal {runes} describing the byte-by-byte state of memory, mass storage, or some file. In {elder days}, debugging was generally done by 'groveling over' a dump (see {grovel}); increasing use of high-level languages and interactive debuggers has made this uncommon, and the term 'dump' now has a faintly archaic flavor. 2. A backup. This usage is typical only at large timesharing installations.

:dumpster diving: /dump'-ster di:'-ving/ n. 1. The practice of sifting refuse from an office or technical installation to extract confidential data, especially security-compromising information ('dumpster' is an Americanism for what is elsewhere called a 'skip'). Back in AT&T's monopoly days, before paper shredders became common office equipment, phone phreaks (see {phreaking}) used to organize regular dumpster runs against phone company plants and offices. Discarded and damaged copies of AT&T internal manuals taught them much. The technique is still rumored to be a favorite of crackers operating against careless targets. 2. The practice of raiding the dumpsters behind buildings where producers and/or consumers of high-tech equipment are located, with the expectation (usually justified) of finding discarded but still-valuable equipment to be nursed back to health in some hacker's den. Experienced dumpster-divers not infrequently accumulate basements full of moldering (but still potentially useful) {cruft}.

:dup killer: /d[y]oop kill'r/ [FidoNet] n. Software that is supposed to detect and delete duplicates of a message that may have reached the FidoNet system via different routes.

:dup loop: /d[y]oop loop/ (also 'dupe loop') [FidoNet] n. An incorrectly configured system or network gateway may propagate duplicate messages on one or more {echo}es, with different identification information that renders {dup killer}s ineffective. If such a duplicate message eventually reaches a system through which it has already passed (with the original identification information), all systems passed on the way back to that system are said to be involved in a {dup loop}.

:dusty deck: n. Old software (especially applications) which one is obliged to remain compatible with (or to maintain). The term implies that the software in question is a holdover from card-punch days. Used esp. when referring to old scientific and {number-crunching} software, much of which was written in FORTRAN and very poorly documented but is believed to be too expensive to replace. See {fossil}.

:DWIM: /dwim/ [acronym, 'Do What I Mean'] 1. adj. Able to guess, sometimes even correctly, the result intended when bogus input was provided. 2. n.,obs. The BBNLISP/INTERLISP function that attempted to accomplish this feat by correcting many of the more common errors. See {hairy}. 3. Occasionally, an interjection hurled at a balky computer, esp. when one senses one might be tripping over legalisms (see {legalese}).

Warren Teitelman originally wrote DWIM to fix his typos and spelling errors, so it was somewhat idiosyncratic to his style, and would often make hash of anyone else's typos if they were stylistically different. This led a number of victims of DWIM to claim the acronym stood for 'Damn Warren's Infernal Machine!'.

In one notorious incident, Warren added a DWIM feature to the command interpreter used at Xerox PARC. One day another hacker there typed 'delete *$' to free up some disk space. (The editor there named backup files by appending '$' to the original file name, so he was trying to delete any backup files left over from old editing sessions.) It happened that there weren't any editor backup files, so DWIM helpfully reported '*$ not found, assuming you meant 'delete *'.' It then started to delete all the files on the disk! The hacker managed to stop it with a {Vulcan nerve pinch} after only a half dozen or so files were lost. The hacker later said he had been sorely tempted to go to Warren's office, tie Warren down in his chair in front of his workstation, and then type 'delete *$' twice.

DWIM is often suggested in jest as a desired feature for a complex program; it is also occasionally described as the single instruction the ideal computer would have. Back when proofs of program correctness were in vogue, there were also jokes about 'DWIMC' (Do What I Mean, Correctly). A related term, more often seen as a verb, is DTRT (Do The Right Thing); see {Right Thing}.

:dynner: /din'r/ 32 bits, by analogy with {nybble} and {{byte}}. Usage: rare and extremely silly. See also {playte}, {tayste}, {crumb}.

= E = =====

:earthquake: [IBM] n. The ultimate real-world shock test for computer hardware. Hackish sources at IBM deny the rumor that the Bay Area quake of 1989 was initiated by the company to test quality-assurance procedures at its California plants.

:Easter egg: [from the custom of the Easter Egg hunt observed in the U.S. and many psparts of Europe] n. 1. A message hidden in the object code of a program as a joke, intended to be found by persons disassembling or browsing the code. 2. A message, graphic, or sound effect emitted by a program (or, on a PC, the BIOS ROM) in response to some undocumented set of commands or keystrokes, intended as a joke or to display program credits. One well-known early Easter egg found in a couple of OSes caused them to respond to the command 'make love' with 'not war?'. Many personal computers have much more elaborate eggs hidden in ROM, including lists of the developers' names, political exhortations, snatches of music, and (in one case) graphics images of the entire development team.

:Easter egging: [IBM] n. The act of replacing unrelated parts more or less at random in hopes that a malfunction will go away. Hackers consider this the normal operating mode of {field circus} techs and do not love them for it. Compare {shotgun debugging}.

:eat flaming death: imp. A construction popularized among hackers by the infamous {CPU Wars} comic; supposed to derive from a famously turgid line in a WWII-era anti-Nazi propaganda comic that ran "Eat flaming death, non-Aryan mongrels!" or something of the sort (however, it is also reported that the Firesign Theater's 1975 album "In The Next World, You're On Your Own" included the phrase "Eat flaming death, fascist media pigs"; this may have been an influence). Used in humorously overblown expressions of hostility. "Eat flaming death, {{EBCDIC}} users!"

:EBCDIC:: /eb's*-dik/, /eb'see'dik/, or /eb'k*-dik/ [abbreviation, Extended Binary Coded Decimal Interchange Code] n. An alleged character set used on IBM {dinosaur}s. It exists in at least six mutually incompatible versions, all featuring such delights as non-contiguous letter sequences and the absence of several ASCII punctuation characters fairly important for modern computer languages (exactly which characters are absent varies according to which version of EBCDIC you're looking at). IBM adapted EBCDIC from {{punched card}} code in the early 1960s and promulgated it as a customer-control tactic (see {connector conspiracy}), spurning the already established ASCII standard. Today, IBM claims to be an open-systems company, but IBM's own description of the EBCDIC variants and how to convert between them is still internally classified top-secret, burn-before-reading. Hackers blanch at the very *name* of EBCDIC and consider it a manifestation of purest {evil}. See also {fear and loathing}.

:echo: [FidoNet] n. A {topic group} on {FidoNet}'s echomail system. Compare {newsgroup}.

:eighty-column mind: [IBM] n. The sort said to be possessed by persons for whom the transition from {punched card} to tape was traumatic (nobody has dared tell them about disks yet). It is said that these people, including (according to an old joke) the founder of IBM, will be buried 'face down, 9-edge first' (the 9-edge being the bottom of the card). This directive is inscribed on IBM's 1402 and 1622 card readers and is referenced in a famous bit of doggerel called "The Last Bug", the climactic lines of which are as follows:

He died at the console Of hunger and thirst. Next day he was buried, Face down, 9-edge first.

The eighty-column mind is thought by most hackers to dominate IBM's customer base and its thinking. See {IBM}, {fear and loathing}, {card walloper}.

:El Camino Bignum: /el' k*-mee'noh big'nuhm/ n. The road mundanely called El Camino Real, a road through the San Francisco peninsula that originally extended all the way down to Mexico City and many portions of which are still intact. Navigation on the San Francisco peninsula is usually done relative to El Camino Real, which defines {logical} north and south even though it isn't really north-south many places. El Camino Real runs right past Stanford University and so is familiar to hackers.

The Spanish word 'real' (which has two syllables: /ray-ahl'/) means 'royal'; El Camino Real is 'the royal road'. In the FORTRAN language, a 'real' quantity is a number typically precise to 7 significant digits, and a 'double precision' quantity is a larger floating-point number, precise to perhaps fourteen significant digits (other languages have similar 'real' types).

When a hacker from MIT visited Stanford in 1976, he remarked what a long road El Camino Real was. Making a pun on 'real', he started calling it 'El Camino Double Precision' —- but when the hacker was told that the road was hundreds of miles long, he renamed it 'El Camino Bignum', and that name has stuck. (See {bignum}.)

:elder days: n. The heroic age of hackerdom (roughly, pre-1980); the era of the {PDP-10}, {TECO}, {{ITS}}, and the ARPANET. This term has been rather consciously adopted from J. R. R. Tolkien's fantasy epic 'The Lord of the Rings'. Compare {Iron Age}; see also {elvish}.

:elegant: [from mathematical usage] adj. Combining simplicity, power, and a certain ineffable grace of design. Higher praise than 'clever', 'winning', or even {cuspy}.

:elephantine: adj. Used of programs or systems that are both conspicuous {hog}s (owing perhaps to poor design founded on {brute force and ignorance}) and exceedingly {hairy} in source form. An elephantine program may be functional and even friendly, but (as in the old joke about being in bed with an elephant) it's tough to have around all the same (and, like a pachyderm, difficult to maintain). In extreme cases, hackers have been known to make trumpeting sounds or perform expressive proboscatory mime at the mention of the offending program. Usage: semi-humorous. Compare 'has the elephant nature' and the somewhat more pejorative {monstrosity}. See also {second-system effect} and {baroque}.

:elevator controller: n. Another archetypal dumb embedded-systems application, like {toaster} (which superseded it). During one period (1983—84) in the deliberations of ANSI X3J11 (the C standardization committee) this was the canonical example of a really stupid, memory-limited computation environment. "You can't require 'printf(3)' to be part of the default runtime library —- what if you're targeting an elevator controller?" Elevator controllers became important rhetorical weapons on both sides of several {holy wars}.

:ELIZA effect: /*-li:'z* *-fekt'/ [AI community] n. The tendency of humans to attach associations to terms from prior experience. For example, there is nothing magic about the symbol '' that makes it well-suited to indicate addition; it's just that people associate it with addition. Using '' or 'plus' to mean addition in a computer language is taking advantage of the ELIZA effect.

This term comes from the famous ELIZA program by Joseph Weizenbaum, which simulated a Rogerian psychoanalyst by rephrasing many of the patient's statements as questions and posing them to the patient. It worked by simple pattern recognition and substitution of key words into canned phrases. It was so convincing, however, that there are many anecdotes about people becoming very emotionally caught up in dealing with ELIZA. All this was due to people's tendency to attach to words meanings which the computer never put there. The ELIZA effect is a {Good Thing} when writing a programming language, but it can blind you to serious shortcomings when analyzing an Artificial Intelligence system. Compare {ad-hockery}; see also {AI-complete}.

:elvish: n. 1. The Tengwar of Feanor, a table of letterforms resembling the beautiful Celtic half-uncial hand of the 'Book of Kells'. Invented and described by J. R. R. Tolkien in 'The Lord of The Rings' as an orthography for his fictional 'elvish' languages, this system (which is both visually and phonetically elegant) has long fascinated hackers (who tend to be interested by artificial languages in general). It is traditional for graphics printers, plotters, window systems, and the like to support a Feanorian typeface as one of their demo items. See also {elder days}. 2. By extension, any odd or unreadable typeface produced by a graphics device. 3. The typeface mundanely called 'B"ocklin', an art-decoish display font.

:EMACS: /ee'maks/ [from Editing MACroS] n. The ne plus ultra of hacker editors, a programmable text editor with an entire LISP system inside it. It was originally written by Richard Stallman in {TECO} under {{ITS}} at the MIT AI lab; AI Memo 554 described it as "an advanced, self-documenting, customizable, extensible real-time display editor". It has since been reimplemented any number of times, by various hackers, and versions exist which run under most major operating systems. Perhaps the most widely used version, also written by Stallman and now called "{GNU} EMACS" or {GNUMACS}, runs principally under UNIX. It includes facilities to run compilation subprocesses and send and receive mail; many hackers spend up to 80% of their {tube time} inside it. Other variants include {GOSMACS}, CCA EMACS, UniPress EMACS, Montgomery EMACS, jove, epsilon, and MicroEMACS.

Some EMACS versions running under window managers iconify as an overflowing kitchen sink, perhaps to suggest the one feature the editor does not (yet) include. Indeed, some hackers find EMACS too heavyweight and {baroque} for their taste, and expand the name as 'Escape Meta Alt Control Shift' to spoof its heavy reliance on keystrokes decorated with {bucky bits}. Other spoof expansions include 'Eight Megabytes And Constantly Swapping', 'Eventually 'malloc()'s All Computer Storage', and 'EMACS Makes A Computer Slow' (see {{recursive acronym}}). See also {vi}.

:email: /ee'mayl/ 1. n. Electronic mail automatically passed through computer networks and/or via modems over common-carrier lines. Contrast {snail-mail}, {paper-net}, {voice-net}. See {network address}. 2. vt. To send electronic mail.

Oddly enough, the word 'emailed' is actually listed in the OED; it means "embossed (with a raised pattern) or arranged in a net work". A use from 1480 is given. The word is derived from French 'emmailleure', network.

:emoticon: /ee-moh'ti-kon/ n. An ASCII glyph used to indicate an emotional state in email or news. Although originally intended mostly as jokes, emoticons (or some other explicit humor indication) are virtually required under certain circumstances in high-volume text-only communication forums such as USENET; the lack of verbal and visual cues can otherwise cause what were intended to be humorous, sarcastic, ironic, or otherwise non-100%-serious comments to be badly misinterpreted (not always even by {newbie}s), resulting in arguments and {flame war}s.

Hundreds of emoticons have been proposed, but only a few are in common use. These include:

:-) 'smiley face' (for humor, laughter, friendliness, occasionally sarcasm)

:-( 'frowney face' (for sadness, anger, or upset)

;-) 'half-smiley' ({ha ha only serious}); also known as 'semi-smiley' or 'winkey face'.

:-/ 'wry face'

(These may become more comprehensible if you tilt your head sideways, to the left.)

The first two listed are by far the most frequently encountered. Hyphenless forms of them are common on CompuServe, GEnie, and BIX; see also {bixie}. On {USENET}, 'smiley' is often used as a generic term synonymous with {emoticon}, as well as specifically for the happy-face emoticon.

It appears that the emoticon was invented by one Scott Fahlman on the CMU {bboard} systems around 1980. He later wrote: "I wish I had saved the original post, or at least recorded the date for posterity, but I had no idea that I was starting something that would soon pollute all the world's communication channels." [GLS confirms that he remembers this original posting].

Note for the {newbie}: Overuse of the smiley is a mark of loserhood! More than one per paragraph is a fairly sure sign that you've gone over the line.

:empire: n. Any of a family of military simulations derived from a game written by Peter Langston many years ago. There are five or six multi-player variants of varying degrees of sophistication, and one single-player version implemented for both UNIX and VMS; the latter is even available as MS-DOS freeware. All are notoriously addictive.

:engine: n. 1. A piece of hardware that encapsulates some function but can't be used without some kind of {front end}. Today we have, especially, 'print engine': the guts of a laser printer. 2. An analogous piece of software; notionally, one that does a lot of noisy crunching, such as a 'database engine'.

The hackish senses of 'engine' are actually close to its original, pre-Industrial-Revolution sense of a skill, clever device, or instrument (the word is cognate to 'ingenuity'). This sense had not been completely eclipsed by the modern connotation of power-transducing machinery in Charles Babbage's time, which explains why he named the stored-program computer that he designed in 1844 the 'Analytical Engine'.

:English: 1. n.,obs. The source code for a program, which may be in any language, as opposed to the linkable or executable binary produced from it by a compiler. The idea behind the term is that to a real hacker, a program written in his favorite programming language is at least as readable as English. Usage: used mostly by old-time hackers, though recognizable in context. 2. The official name of the database language used by the Pick Operating System, actually a sort of crufty, brain-damaged SQL with delusions of grandeur. The name permits {marketroid}s to say "Yes, and you can program our computers in English!" to ignorant {suit}s without quite running afoul of the truth-in-advertising laws.

:enhancement: n. {Marketroid}-speak for a bug {fix}. This abuse of language is a popular and time-tested way to turn incompetence into increased revenue. A hacker being ironic would instead call the fix a {feature} —- or perhaps save some effort by declaring the bug itself to be a feature.

:ENQ: /enkw/ or /enk/ [from the ASCII mnemonic ENQuire for 0000101] An on-line convention for querying someone's availability. After opening a {talk mode} connection to someone apparently in heavy hack mode, one might type 'SYN SYN ENQ?' (the SYNs representing notional synchronization bytes), and expect a return of {ACK} or {NAK} depending on whether or not the person felt interruptible. Compare {ping}, {finger}, and the usage of 'FOO?' listed under {talk mode}.

:EOF: /E-O-F/ [abbreviation, 'End Of File'] n. 1. [techspeak] Refers esp. to whatever {out-of-band} value is returned by C's sequential character-input functions (and their equivalents in other environments) when end of file has been reached. This value is -1 under C libraries postdating V6 UNIX, but was originally 0. 2. [UNIX] The keyboard character (usually control-D, the ASCII EOT (End Of Transmission) character) which is mapped by the terminal driver into an end-of-file condition. 3. Used by extension in non-computer contexts when a human is doing something that can be modeled as a sequential read and can't go further. "Yeah, I looked for a list of 360 mnemonics to post as a joke, but I hit EOF pretty fast; all the library had was a {JCL} manual." See also {EOL}.

:EOL: /E-O-L/ [End Of Line] n. Syn. for {newline}, derived perhaps from the original CDC6600 Pascal. Now rare, but widely recognized and occasionally used for brevity. Used in the example entry under {BNF}. See also {EOF}.

:EOU: /E-O-U/ n. The mnemonic of a mythical ASCII control character (End Of User) that could make an ASR-33 Teletype explode on receipt. This parodied the numerous obscure delimiter and control characters left in ASCII from the days when it was associated more with wire-service teletypes than computers (e.g., FS, GS, RS, US, EM, SUB, ETX, and esp. EOT). It is worth remembering that ASR-33s were big, noisy mechanical beasts with a lot of clattering parts; the notion that one might explode was nowhere near as ridiculous as it might seem to someone sitting in front of a {tube} or flatscreen today.

:epoch: [UNIX: prob. from astronomical timekeeping] n. The time and date corresponding to 0 in an operating system's clock and timestamp values. Under most UNIX versions the epoch is 00:00:00 GMT, January 1, 1970; under VMS, it's 00:00:00 GMT of November 17, 1858 (base date of the U.S. Naval Observatory's ephemerides). System time is measured in seconds or {tick}s past the epoch. Weird problems may ensue when the clock wraps around (see {wrap around}), which is not necessarily a rare event; on systems counting 10 ticks per second, a signed 32-bit count of ticks is good only for 6.8 years. The 1-tick-per-second clock of UNIX is good only until January 18, 2038, assuming at least some software continues to consider it signed and that word lengths don't increase by then. See also {wall time}.

:epsilon: [see {delta}] 1. n. A small quantity of anything. "The cost is epsilon." 2. adj. Very small, negligible; less than {marginal}. "We can get this feature for epsilon cost." 3. 'within epsilon of': close enough to be indistinguishable for all practical purposes. This is even closer than being 'within delta of'. "That's not what I asked for, but it's within epsilon of what I wanted." Alternatively, it may mean not close enough, but very little is required to get it there: "My program is within epsilon of working."

:epsilon squared: n. A quantity even smaller than {epsilon}, as small in comparison to epsilon as epsilon is to something normal; completely negligible. If you buy a supercomputer for a million dollars, the cost of the thousand-dollar terminal to go with it is {epsilon}, and the cost of the ten-dollar cable to connect them is epsilon squared. Compare {lost in the underflow}, {lost in the noise}.

:era, the: Syn. {epoch}. Webster's Unabridged makes these words almost synonymous, but 'era' usually connotes a span of time rather than a point in time. The {epoch} usage is recommended.

:Eric Conspiracy: n. A shadowy group of mustachioed hackers named Eric first pinpointed as a sinister conspiracy by an infamous talk.bizarre posting ca. 1986; this was doubtless influenced by the numerous 'Eric' jokes in the Monty Python oeuvre. There do indeed seem to be considerably more mustachioed Erics in hackerdom than the frequency of these three traits can account for unless they are correlated in some arcane way. Well-known examples include Eric Allman (he of the 'Allman style' described under {indent style}) and Erik Fair (co-author of NNTP); your editor has heard from about fourteen others by email, and the organization line 'Eric Conspiracy Secret Laboratories' now emanates regularly from more than one site.

:Eris: /e'ris/ n. The Greek goddess of Chaos, Discord, Confusion, and Things You Know Not Of; her name was latinized to Discordia and she was worshiped by that name in Rome. Not a very friendly deity in the Classical original, she was reinvented as a more benign personification of creative anarchy starting in 1959 by the adherents of {Discordianism} and has since been a semi-serious subject of veneration in several 'fringe' cultures, including hackerdom. See {Discordianism}, {Church of the SubGenius}.

:erotics: /ee-ro'tiks/ n. [Helsinki University of Technology, Finland] n. English-language university slang for electronics. Often used by hackers in Helsinki, maybe because good electronics excites them and makes them warm.

:error 33: [XEROX PARC] n. 1. Predicating one research effort upon the success of another. 2. Allowing your own research effort to be placed on the critical path of some other project (be it a research effort or not).

:essentials: n. Things necessary to maintain a productive and secure hacking environment. "A jug of wine, a loaf of bread, a 20-megahertz 80386 box with 8 meg of core and a 300-megabyte disk supporting full UNIX with source and X windows and EMACS and UUCP via a 'blazer to a friendly Internet site, and thou."

:evil: adj. As used by hackers, implies that some system, program, person, or institution is sufficiently maldesigned as to be not worth the bother of dealing with. Unlike the adjectives in the {cretinous}/{losing}/{brain-damaged} series, 'evil' does not imply incompetence or bad design, but rather a set of goals or design criteria fatally incompatible with the speaker's. This is more an esthetic and engineering judgment than a moral one in the mainstream sense. "We thought about adding a {Blue Glue} interface but decided it was too evil to deal with." "{TECO} is neat, but it can be pretty evil if you're prone to typos." Often pronounced with the first syllable lengthened, as /eeee'vil/.

:exa-: /ek's*/ [SI] pref. See {{quantifiers}}.

:examining the entrails: n. The process of {grovel}ling through a core dump or hex image in the attempt to discover the bug that brought a program or system down. The reference is to divination from the entrails of a sacrified animal. Compare {runes}, {incantation}, {black art}, {desk check}.

:EXCH: /eks'ch*/ or /eksch/ vt. To exchange two things, each for the other; to swap places. If you point to two people sitting down and say "Exch!", you are asking them to trade places. EXCH, meaning EXCHange, was originally the name of a PDP-10 instruction that exchanged the contents of a register and a memory location. Many newer hackers tend to be thinking instead of the {PostScript} exchange operator (which is usually written in lowercase).

:excl: /eks'kl/ n. Abbreviation for 'exclamation point'. See {bang}, {shriek}, {{ASCII}}.

:EXE: /eks'ee/ or /eek'see/ or /E-X-E/ n. An executable binary file. Some operating systems (notably MS-DOS, VMS, and TWENEX) use the extension .EXE to mark such files. This usage is also occasionally found among UNIX programmers even though UNIX executables don't have any required suffix.

:exec: /eg-zek'/ vt.,n. 1. [UNIX: from 'execute'] Synonym for {chain}, derives from the 'exec(2)' call. 2. [from 'executive'] obs. The command interpreter for an {OS} (see {shell}); term esp. used around mainframes, and prob. derived from UNIVAC's archaic EXEC 2 and EXEC 8 operating systems. 3. At IBM and VM/CMS shops, the equivalent of a shell command file (among VM/CMS users).

The mainstream 'exec' as an abbreviation for (human) executive is *not* used. To a hacker, an 'exec' is a always a program, never a person.

:exercise, left as an: [from technical books] Used to complete a proof when one doesn't mind a {handwave}, or to avoid one entirely. The complete phrase is: "The proof (or the rest) is left as an exercise for the reader." This comment *has* occasionally been attached to unsolved research problems by authors possessed of either an evil sense of humor or a vast faith in the capabilities of their audiences.

:eyeball search: n. To look for something in a mass of code or data with one's own native optical sensors, as opposed to using some sort of pattern matching software like {grep} or any other automated search tool. Also called a {vgrep}; compare {vdiff}, {desk check}.

= F = =====

:fab: /fab/ [from 'fabricate'] v. 1. To produce chips from a design that may have been created by someone at another company. Fabbing chips based on the designs of others is the activity of a {silicon foundry}. To a hacker, 'fab' is practically never short for 'fabulous'. 2. 'fab line': the production system (lithography, diffusion, etching, etc.) for chips at a chip manufacturer. Different 'fab lines' are run with different process parameters, die sizes, or technologies, or simply to provide more manufacturing volume.

:face time: n. Time spent interacting with somebody face-to-face (as opposed to via electronic links). "Oh, yeah, I spent some face time with him at the last Usenix."

:factor: n. See {coefficient of X}.

:fall over: [IBM] vi. Yet another synonym for {crash} or {lose}. 'Fall over hard' equates to {crash and burn}.

:fall through: v. (n. 'fallthrough', var. 'fall-through') 1. To exit a loop by exhaustion, i.e., by having fulfilled its exit condition rather than via a break or exception condition that exits from the middle of it. This usage appears to be *really* old, dating from the 1940s and 1950s. 2. To fail a test that would have passed control to a subroutine or some other distant portion of code. 3. In C, 'fall-through' occurs when the flow of execution in a switch statement reaches a 'case' label other than by jumping there from the switch header, passing a point where one would normally expect to find a 'break'. A trivial example:

switch (color) { case GREEN: dogreen(); break; case PINK: dopink(); /* FALL THROUGH */ case RED: dored(); break; default: doblue(); break; }

The variant spelling '/* FALL THRU */' is also common.

The effect of this code is to 'do_green()' when color is 'GREEN', 'do_red()' when color is 'RED', 'do_blue()' on any other color other than 'PINK', and (and this is the important part) 'do_pink()' *and then* 'do_red()' when color is 'PINK'. Fall-through is {considered harmful} by some, though there are contexts (such as the coding of state machines) in which it is natural; it is generally considered good practice to include a comment highlighting the fall-through where one would normally expect a break.

:fandango on core: [UNIX/C hackers, from the Mexican dance] n. In C, a wild pointer that runs out of bounds, causing a {core dump}, or corrupts the 'malloc(3)' {arena} in such a way as to cause mysterious failures later on, is sometimes said to have 'done a fandango on core'. On low-end personal machines without an MMU, this can corrupt the OS itself, causing massive lossage. Other frenetic dances such as the rhumba, cha-cha, or watusi, may be substituted. See {aliasing bug}, {precedence lossage}, {smash the stack}, {memory leak}, {memory smash}, {overrun screw}, {core}.

:FAQ list: /F-A-Q list/ or /fak list/ [USENET] n. A compendium of accumulated lore, posted periodically to high-volume newsgroups in an attempt to forestall Frequently Asked Questions. This lexicon itself serves as a good example of a collection of one kind of lore, although it is far too big for a regular posting. Examples: "What is the proper type of NULL?" and "What's that funny name for the '#' character?" are both Frequently Asked Questions. Several extant FAQ lists do (or should) make reference to the Jargon File (the on-line version of this lexicon).

:FAQL: /fa'kl/ n. Syn. {FAQ list}.

:farming: [Adelaide University, Australia] n. What the heads of a disk drive are said to do when they plow little furrows in the magnetic media. Associated with a {crash}. Typically used as follows: "Oh no, the machine has just crashed; I hope the hard drive hasn't gone {farming} again."

:fascist: adj. 1. Said of a computer system with excessive or annoying security barriers, usage limits, or access policies. The implication is that said policies are preventing hackers from getting interesting work done. The variant 'fascistic' seems to have been preferred at MIT, poss. by analogy with 'touristic' (see {tourist}). 2. In the design of languages and other software tools, 'the fascist alternative' is the most restrictive and structured way of capturing a particular function; the implication is that this may be desirable in order to simplify the implementation or provide tighter error checking. Compare {bondage-and-discipline language}, but that term is global rather than local.

:fat electrons: n. Old-time hacker David Cargill's theory on the causation of computer glitches. Your typical electric utility draws its line current out of the big generators with a pair of coil taps located near the top of the dynamo. When the normal tap brushes get dirty, they take them off line to clean up, and use special auxiliary taps on the *bottom* of the coil. Now, this is a problem, because when they do that they get not ordinary or 'thin' electrons, but the fat'n'sloppy electrons that are heavier and so settle to the bottom of the generator. These flow down ordinary wires just fine, but when they have to turn a sharp corner (as in an integrated-circuit via) they're apt to get stuck. This is what causes computer glitches. [Fascinating. Obviously, fat electrons must gain mass by {bogon} absorption —- ESR] Compare {bogon}, {magic smoke}.

:faulty: adj. Non-functional; buggy. Same denotation as {bletcherous}, {losing}, q.v., but the connotation is much milder.

:fd leak: /F-D leek/ n. A kind of programming bug analogous to a {core leak}, in which a program fails to close file descriptors ('fd's) after file operations are completed, and thus eventually runs out of them. See {leak}.

:fear and loathing: [from Hunter Thompson] n. A state inspired by the prospect of dealing with certain real-world systems and standards that are totally {brain-damaged} but ubiquitous —- Intel 8086s, or {COBOL}, or {{EBCDIC}}, or any {IBM} machine except the Rios (a.k.a. the RS/6000). "Ack! They want PCs to be able to talk to the AI machine. Fear and loathing time!"

:feature: n. 1. A good property or behavior (as of a program). Whether it was intended or not is immaterial. 2. An intended property or behavior (as of a program). Whether it is good or not is immaterial (but if bad, it is also a {misfeature}). 3. A surprising property or behavior; in particular, one that is purposely inconsistent because it works better that way —- such an inconsistency is therefore a {feature} and not a {bug}. This kind of feature is sometimes called a {miswart}; see that entry for a classic example. 4. A property or behavior that is gratuitous or unnecessary, though perhaps also impressive or cute. For example, one feature of Common LISP's 'format' function is the ability to print numbers in two different Roman-numeral formats (see {bells, whistles, and gongs}). 5. A property or behavior that was put in to help someone else but that happens to be in your way. 6. A bug that has been documented. To call something a feature sometimes means the author of the program did not consider the particular case, and that the program responded in a way that was unexpected but not strictly incorrect. A standard joke is that a bug can be turned into a {feature} simply by documenting it (then theoretically no one can complain about it because it's in the manual), or even by simply declaring it to be good. "That's not a bug, that's a feature!" is a common catchphrase. See also {feetch feetch}, {creeping featurism}, {wart}, {green lightning}.

The relationship among bugs, features, misfeatures, warts, and miswarts might be clarified by the following hypothetical exchange between two hackers on an airliner:

A: "This seat doesn't recline."

B: "That's not a bug, that's a feature. There is an emergency exit door built around the window behind you, and the route has to be kept clear."

A: "Oh. Then it's a misfeature; they should have increased the spacing between rows here."

B: "Yes. But if they'd increased spacing in only one section it would have been a wart —- they would've had to make nonstandard-length ceiling panels to fit over the displaced seats."

A: "A miswart, actually. If they increased spacing throughout they'd lose several rows and a chunk out of the profit margin. So unequal spacing would actually be the Right Thing."

B: "Indeed."

'Undocumented feature' is a common, allegedly humorous euphemism for a {bug}.

:feature creature: [poss. fr. slang 'creature feature' for a horror movie] n. 1. One who loves to add features to designs or programs, perhaps at the expense of coherence, concision, or {taste}. 2. Alternately, a semi-mythical being that induces otherwise rational programmers to perpetrate such crocks. See also {feeping creaturism}, {creeping featurism}.

:feature key: n. The Macintosh key with the cloverleaf graphic on its keytop; sometimes referred to as 'flower', 'pretzel', 'clover', 'propeller', 'beanie' (an apparent reference to the major feature of a propeller beanie), {splat}, or the 'command key'. The Mac's equivalent of an {alt} key. The proliferation of terms for this creature may illustrate one subtle peril of iconic interfaces.

Many people have been mystified by the cloverleaf-like symbol that appears on the feature key. Its oldest name is 'cross of St. Hannes', but it occurs in pre-Christian Viking art as a decorative motif. Throughout Scandinavia today the road agencies use it to mark sites of historical interest. Many of these are old churches; hence, the Swedish idiom for the symbol is 'kyrka', cognate to English 'church' and Scots-dialect 'kirk' but pronounced /shir'k*/ in modern Swedish. This is in fact where Apple got the symbol; they give the translation "interesting feature"!

:feature shock: [from Alvin Toffler's book title 'Future Shock'] n. A user's (or programmer's!) confusion when confronted with a package that has too many features and poor introductory material.

:featurectomy: /fee'ch*r-ek't*-mee/ n. The act of removing a feature from a program. Featurectomies come in two flavors, the 'righteous' and the 'reluctant'. Righteous featurectomies are performed because the remover believes the program would be more elegant without the feature, or there is already an equivalent and better way to achieve the same end. (This is not quite the same thing as removing a {misfeature}.) Reluctant featurectomies are performed to satisfy some external constraint such as code size or execution speed.

:feep: /feep/ 1. n. The soft electronic 'bell' sound of a display terminal (except for a VT-52); a beep (in fact, the microcomputer world seems to prefer {beep}). 2. vi. To cause the display to make a feep sound. ASR-33s (the original TTYs) do not feep; they have mechanical bells that ring. Alternate forms: {beep}, 'bleep', or just about anything suitably onomatopoeic. (Jeff MacNelly, in his comic strip "Shoe", uses the word 'eep' for sounds made by computer terminals and video games; this is perhaps the closest written approximation yet.) The term 'breedle' was sometimes heard at SAIL, where the terminal bleepers are not particularly soft (they sound more like the musical equivalent of a raspberry or Bronx cheer; for a close approximation, imagine the sound of a Star Trek communicator's beep lasting for 5 seconds). The 'feeper' on a VT-52 has been compared to the sound of a '52 Chevy stripping its gears. See also {ding}.

:feeper: /fee'pr/ n. The device in a terminal or workstation (usually a loudspeaker of some kind) that makes the {feep} sound.

:feeping creature: [from {feeping creaturism}] n. An unnecessary feature; a bit of {chrome} that, in the speaker's judgment, is the camel's nose for a whole horde of new features.

:feeping creaturism: /fee'ping kree'ch*r-izm/ n. A deliberate spoonerism for {creeping featurism}, meant to imply that the system or program in question has become a misshapen creature of hacks. This term isn't really well defined, but it sounds so neat that most hackers have said or heard it. It is probably reinforced by an image of terminals prowling about in the dark making their customary noises.

:feetch feetch: /feech feech/ interj. If someone tells you about some new improvement to a program, you might respond: "Feetch, feetch!" The meaning of this depends critically on vocal inflection. With enthusiasm, it means something like "Boy, that's great! What a great hack!" Grudgingly or with obvious doubt, it means "I don't know; it sounds like just one more unnecessary and complicated thing". With a tone of resignation, it means, "Well, I'd rather keep it simple, but I suppose it has to be done".

:fence: n. 1. A sequence of one or more distinguished ({out-of-band}) characters (or other data items), used to delimit a piece of data intended to be treated as a unit (the computer-science literature calls this a 'sentinel'). The NUL (ASCII 0000000) character that terminates strings in C is a fence. Hex FF is also (though slightly less frequently) used this way. See {zigamorph}. 2. [among users of optimizing compilers] Any technique, usually exploiting knowledge about the compiler, that blocks certain optimizations. Used when explicit mechanisms are not available or are overkill. Typically a hack: "I call a dummy procedure there to force a flush of the optimizer's register-coloring info" can be expressed by the shorter "That's a fence procedure".

:fencepost error: n. 1. A problem with the discrete equivalent of a boundary condition. Often exhibited in programs by iterative loops. From the following problem: "If you build a fence 100 feet long with posts 10 feet apart, how many posts do you need?" Either 9 or 11 is a better answer than the obvious 10. For example, suppose you have a long list or array of items, and want to process items m through n; how many items are there? The obvious answer is n - m, but that is off by one; the right answer is n - m + 1. A program that used the 'obvious' formula would have a fencepost error in it. See also {zeroth} and {off-by-one error}, and note that not all off-by-one errors are fencepost errors. The game of Musical Chairs involves a catastrophic off-by-one error where N people try to sit in N - 1 chairs, but it's not a fencepost error. Fencepost errors come from counting things rather than the spaces between them, or vice versa, or by neglecting to consider whether one should count one or both ends of a row. 2. Occasionally, an error induced by unexpectedly regular spacing of inputs, which can (for instance) screw up your hash table.

:fepped out: /fept owt/ adj. The Symbolics 3600 Lisp Machine has a Front-End Processor called a 'FEP' (compare sense 2 of {box}). When the main processor gets {wedged}, the FEP takes control of the keyboard and screen. Such a machine is said to have 'fepped out'.

:FidoNet: n. A worldwide hobbyist network of personal computers which exchange mail, discussion groups, and files. Founded in 1984 and originally consisting only of IBM PCs and compatibles, FidoNet now includes such diverse machines as Apple ][s, Ataris, Amigas, and UNIX systems. Though it is much younger than {USENET}, FidoNet is already (in early 1991) a significant fraction of USENET's size at some 8000 systems.

:field circus: [a derogatory pun on 'field service'] n. The field service organization of any hardware manufacturer, but especially DEC. There is an entire genre of jokes about DEC field circus engineers:

Q: How can you recognize a DEC field circus engineer with a flat tire? A: He's changing one tire at a time to see which one is flat.

Q: How can you recognize a DEC field circus engineer who is out of gas? A: He's changing one tire at a time to see which one is flat.

[See {Easter egging} for additional insight on these jokes.] There is also the 'Field Circus Cheer' (from the {plan file} for DEC on MIT-AI):

Maynard! Maynard! Don't mess with us! We're mean and we're tough! If you get us confused We'll screw up your stuff.

(DEC's service HQ is located in Maynard, Massachusetts.)

:field servoid: [play on 'android'] /fee'ld ser'voyd/ n. Representative of a field service organization (see {field circus}). This has many of the implications of {droid}.

:Fight-o-net: [FidoNet] n. Deliberate distortion of {FidoNet}, often applied after a flurry of {flamage} in a particular {echo}, especially the SYSOP echo or Fidonews (see {'Snooze}).

:File Attach: [FidoNet] 1. n. A file sent along with a mail message from one BBS to another. 2. vt. Sending someone a file by using the File Attach option in a BBS mailer.

:File Request: [FidoNet] 1. n. The {FidoNet} equivalent of {FTP}, in which one BBS system automatically dials another and {snarf}s one or more files. Often abbreviated 'FReq'; files are often announced as being "available for FReq" in the same way that files are announced as being "available for/by anonymous FTP" on the Internet. 2. vt. The act of getting a copy of a file by using the File Request option of the BBS mailer.

:file signature: n. A {magic number} sense 3.

:filk: /filk/ [from SF fandom, where a typo for 'folk' was adopted as a new word] n.,v. A 'filk' is a popular or folk song with lyrics revised or completely new lyrics, intended for humorous effect when read and/or to be sung late at night at SF conventions. There is a flourishing subgenre of these called 'computer filks', written by hackers and often containing rather sophisticated technical humor. See {double bucky} for an example. Compare {hing} and {newsfroup}.

:film at 11: [MIT: in parody of TV newscasters] 1. Used in conversation to announce ordinary events, with a sarcastic implication that these events are earth-shattering. "{{ITS}} crashes; film at 11." "Bug found in scheduler; film at 11." 2. Also widely used outside MIT to indicate that additional information will be available at some future time, *without* the implication of anything particularly ordinary about the referenced event. For example, "The mail file server died this morning; we found garbage all over the root directory. Film at 11." would indicate that a major failure had occurred but the people working on it have no additional information about it. Use of the phrase in this way suggests gently people would appreciate it if users would quit bothering them and wait for the 11:00 news for additional information.