Part 15

: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.