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

higher {spl} level). Then another machine tries to reach either the down machine or the pseudo-down machine, and itself becomes pseudo-down. The first machine to discover the down one is now trying both to access the down one and to respond to the pseudo-down one, so it is even harder to reach. This situation snowballs very fast, and soon the entire network of machines is frozen --- worst of all, the user can't even abort the file access that started the problem! Many of NFS'es problems are excused by partisans as being an inevitable result of its statelessness, which is held to be a great feature (critics, of course, call it a great {misfeature}). (ITS partisans are apt to cite this as proof of UNIX's alleged bogosity; ITS had a working NFS-like shared file system with none of these problems in the early 1970s.) See also {broadcast storm}.

:NIL: /nil/ No. Used in reply to a question, particularly one asked using the -P' convention. Most hackers assume this derives simply from LISP terminology forfalse' (see also {T}), but NIL as a negative reply was well-established among radio hams decades before the advent of LISP. The historical connection between early hackerdom and the ham radio word was strong enough that this may have been an influence.

:NMI: /N-M-I/ n. Non-Maskable Interrupt. An IRQ 7 on the PDP-11

or 680[01234]0; the NMI line on an 80[1234]86. In contrast with a {priority interrupt} (which might be ignored, although that is unlikely), an NMI is never ignored.

:no-op: /noh'op/ alt. NOP /nop/ [no operation] n. 1. (also v.) A machine instruction that does nothing (sometimes used in assembler-level programming as filler for data or patch areas, or to overwrite code to be removed in binaries). See also {JFCL}.

A person who contributes nothing to a project, or has nothing going on upstairs, or both. As in "He's a no-op." 3. Any operation or sequence of operations with no effect, such as circling the block without finding a parking space, or putting money into a vending machine and having it fall immediately into the coin-return box, or asking someone for help and being told to go away. "Oh, well, that was a no-op." Hot-and-sour soup (see {great-wall}) that is insufficiently either is `no-op soup'; so is wonton soup if everybody else is having hot-and-sour.

:noddy: /nod'ee/ [UK: from the children's books] adj.

Small and un-useful, but demonstrating a point. Noddy programs are often written by people learning a new language or system. The archetypal noddy program is {hello, world}. Noddy code may be used to demonstrate a feature or bug of a compiler. May be used of real hardware or software to imply that it isn't worth using.

"This editor's a bit noddy." 2. A program that is more or less instant to produce. In this use, the term does not necessarily connote uselessness, but describes a {hack} sufficiently trivial that it can be written and debugged while carrying on (and during the space of) a normal conversation. "I'll just throw together a noddy {awk} script to dump all the first fields." In North America this might be called a {mickey mouse program}. See {toy program}.

:NOMEX underwear: /noh'meks uhn'-der-weir/ [USENET] n. Syn.

{asbestos longjohns}, used mostly in auto-related mailing lists and newsgroups. NOMEX underwear is an actual product available on the racing equipment market, used as a fire resistance measure and required in some racing series.

:Nominal Semidestructor: n. Sound-alike slang for `National Semiconductor', found among other places in the 4.3BSD networking sources. During the late 1970s to mid-1980s this company marketed a series of microprocessors including the NS16000 and NS32000 and several variants. At one point early in the great microprocessor race, the specs on these chips made them look like serious competition for the rising Intel 80x86 and Motorola 680x0 series.

Unfortunately, the actual parts were notoriously flaky and never implemented the full instruction set promised in their literature, apparently because the company couldn't get any of the mask steppings to work as designed. They eventually sank without trace, joining the Zilog Z80,000 and a few even more obscure also-rans in the graveyard of forgotten microprocessors. Compare {HP-SUX}, {AIDX}, {buglix}, {Macintrash}, {Telerat}, {Open DeathTrap}, {ScumOS}, {sun-stools}.

:non-optimal solution: n. (also `sub-optimal solution') An astoundingly stupid way to do something. This term is generally used in deadpan sarcasm, as its impact is greatest when the person speaking looks completely serious. Compare {stunning}. See also {Bad Thing}.

:nonlinear: adj. [scientific computation] 1. Behaving in an erratic and unpredictable fashion; unstable. When used to describe the behavior of a machine or program, it suggests that said machine or program is being forced to run far outside of design specifications. This behavior may be induced by unreasonable inputs, or may be triggered when a more mundane bug sends the computation far off from its expected course. 2. When describing the behavior of a person, suggests a tantrum or a {flame}.

"When you talk to Bob, don't mention the drug problem or he'll go nonlinear for hours." In this context, go nonlinear' connotesblow up out of proportion' (proportion connotes linearity).

:nontrivial: adj. Requiring real thought or significant computing power. Often used as an understated way of saying that a problem is quite difficult or impractical, or even entirely unsolvable ("Proving P=NP is nontrivial"). The preferred emphatic form is `decidedly nontrivial'. See {trivial}, {uninteresting}, {interesting}.

:notwork: /not'werk/ n. A network, when it is acting {flaky} or is {down}. Compare {nyetwork}. Said at IBM to have orig.

referred to a particular period of flakiness on IBM's VNET

corporate network, ca. 1988; but there are independent reports of the term from elsewhere.

:NP-: /N-P/ pref. Extremely. Used to modify adjectives describing a level or quality of difficulty; the connotation is often more so than it should be' (NP-complete problems all seem to be very hard, but so far no one has found a good a priori reason that they should be.) "Coding a BitBlt implementation to perform correctly in every case is NP-annoying." This is generalized from the computer-science termsNP-hard' and NP-complete'. NP is the set of Nondeterministic-Polynomial algorithms, those that can be completed by a nondeterministic Turing machine in an amount of time that is a polynomial function of the size of the input; a solution for one NP-complete problem would solve all the others. Note, however, that the NP- prefix is, from a complexity theorist's point of view, the wrong part ofNP-complete' to connote extreme difficulty; it is the completeness, not the NP-ness, that puts any problem it describes in the `hard' category.

:nroff: /en'rof/ [UNIX, from "new runoff"] n. A companion program to the UNIX typesetter `troff', accepting identical input but preparing output for terminals and line printers.

:NSA line eater: n. The National Security Agency trawling program sometimes assumed to be reading {USENET} for the U.S. Government's spooks. Most hackers describe it as a mythical beast, but some believe it actually exists, more aren't sure, and many believe in acting as though it exists just in case. Some netters put loaded phrases like KGB',Uzi', nuclear materials',Palestine', cocaine', andassassination' in their {sig block}s in a (probably futile) attempt to confuse and overload the creature. The {GNU} version of {EMACS} actually has a command that randomly inserts a bunch of insidious anarcho-verbiage into your edited text.

There is a mainstream variant of this myth involving a `Trunk Line Monitor', which supposedly used speech recognition to extract words from telephone trunks. This one was making the rounds in the late 1970s, spread by people who had no idea of then-current technology or the storage, signal-processing, or speech recognition needs of such a project. On the basis of mass-storage costs alone it would have been cheaper to hire 50 high-school students and just let them listen in. Speech-recognition technology can't do this job even now (1991), and almost certainly won't in this millennium, either. The peak of silliness came with a letter to an alternative paper in New Haven, Connecticut, laying out the factoids of this Big Brotherly affair. The letter writer then revealed his actual agenda by offering --- at an amazing low price, just this once, we take VISA and MasterCard --- a scrambler guaranteed to daunt the Trunk Trawler and presumably allowing the would-be Baader-Meinhof gangs of the world to get on with their business.

:nuke: vt. 1. To intentionally delete the entire contents of a given directory or storage volume. "On UNIX, `rm -r /usr'

will nuke everything in the usr filesystem." Never used for accidental deletion. Oppose {blow away}. 2. Syn. for {dike}, applied to smaller things such as files, features, or code sections. Often used to express a final verdict. "What do you want me to do with that 80-meg {wallpaper} file?" "Nuke it." 3. Used of processes as well as files; nuke is a frequent verbal alias for kill -9' on UNIX. 4. On IBM PCs, a bug that results in {fandango on core} can trash the operating system, including the FAT (the in-core copy of the disk block chaining information). This can utterly scramble attached disks, which are then said to have beennuked'. This term is also used of analogous lossages on Macintoshes