The Hacker's Dictionary, - [best reads of all time .txt] 📗

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 *' ormkfs' on a mounted file system. Compare {adger}.

:dumbed down: adj. Simplified, with a strong connotation of oversimplified. 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 askip'). 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}.

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: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' withnot 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