Chapter D: C. Power Lab n (6)

The adjective `long-haired' is well-attested to have been in slang use among scientists and engineers during the early 1950s; it was equivalent to modern `hairy' senses 1 and 2, and was very likely ancestral to the hackish use. In fact the noun `long-hair' was at the time used to describe a person satisfying sense 3. Both senses probably passed out of use when long hair was adopted as a signature trait by the 1960s counterculture, leaving hackish `hairy' as a sort of stunted mutant relic.

In British mainstream use, "hairy" means "dangerous", and consequently, in British programming terms, "hairy" may be used to denote complicated and/or incomprehensible code, but only if that complexity or incomprehesiveness is also considered dangerous.

Node:HAKMEM, Next:hakspek, Previous:hairy, Up:= H =

HAKMEM /hak'mem/ n.

MIT AI Memo 239 (February 1972). A legendary collection of neat mathematical and programming hacks contributed by many people at MIT and elsewhere. (The title of the memo really is "HAKMEM", which is a 6-letterism for `hacks memo'.) Some of them are very useful techniques, powerful theorems, or interesting unsolved problems, but most fall into the category of mathematical and computer trivia. Here is a sampling of the entries (with authors), slightly paraphrased:

Item 41 (Gene Salamin): There are exactly 23,000 prime numbers less than 2^(18).

Item 46 (Rich Schroeppel): The most probable suit distribution in bridge hands is 4-4-3-2, as compared to 4-3-3-3, which is the most evenly distributed. This is because the world likes to have unequal numbers: a thermodynamic effect saying things will not be in the state of lowest energy, but in the state of lowest disordered energy.

Item 81 (Rich Schroeppel): Count the magic squares of order 5 (that is, all the 5-by-5 arrangements of the numbers from 1 to 25 such that all rows, columns, and diagonals add up to the same number). There are about 320 million, not counting those that differ only by rotation and reflection.

Item 154 (Bill Gosper): The myth that any given programming language is machine independent is easily exploded by computing the sum of powers of 2. If the result loops with period = 1 with sign +, you are on a sign-magnitude machine. If the result loops with period = 1 at -1, you are on a twos-complement machine. If the result loops with period greater than 1, including the beginning, you are on a ones-complement machine. If the result loops with period greater than 1, not including the beginning, your machine isn't binary -- the pattern should tell you the base. If you run out of memory, you are on a string or bignum system. If arithmetic overflow is a fatal error, some fascist pig with a read-only mind is trying to enforce machine independence. But the very ability to trap overflow is machine dependent. By this strategy, consider the universe, or, more precisely, algebra: Let X = the sum of many powers of 2 = ...111111 (base 2). Now add X to itself: X + X = ...111110. Thus, 2X = X - 1, so X = -1. Therefore algebra is run on a machine (the universe) that is two's-complement.

Item 174 (Bill Gosper and Stuart Nelson): 21963283741 is the only number such that if you represent it on the PDP-10 as both an integer and a floating-point number, the bit patterns of the two representations are identical.

Item 176 (Gosper): The "banana phenomenon" was encountered when processing a character string by taking the last 3 letters typed out, searching for a random occurrence of that sequence in the text, taking the letter following that occurrence, typing it out, and iterating. This ensures that every 4-letter string output occurs in the original. The program typed BANANANANANANANA.... We note an ambiguity in the phrase, "the Nth occurrence of." In one sense, there are five 00's in 0000000000; in another, there are nine. The editing program TECO finds five. Thus it finds only the first ANA in BANANA, and is thus obligated to type N next. By Murphy's Law, there is but one NAN, thus forcing A, and thus a loop. An option to find overlapped instances would be useful, although it would require backing up N - 1 characters before seeking the next N-character string.

Note: This last item refers to a Dissociated Press implementation. See also banana problem.

HAKMEM also contains some rather more complicated mathematical and technical items, but these examples show some of its fun flavor.

An HTML transcription of the entire document is available at http://www.inwap.com/pdp10/hbaker/hakmem/hakmem.html.

Node:hakspek, Next:Halloween Documents, Previous:HAKMEM, Up:= H =

hakspek /hak'speek/ n.

A shorthand method of spelling found on many British academic bulletin boards and talker systems. Syllables and whole words in a sentence are replaced by single ASCII characters the names of which are phonetically similar or equivalent, while multiple letters are usually dropped. Hence, `for' becomes `4'; `two', `too', and `to' become `2'; `ck' becomes `k'. "Before I see you tomorrow" becomes "b4 i c u 2moro". First appeared in London about 1986, and was probably caused by the slowness of available talker systems, which operated on archaic machines with outdated operating systems and no standard methods of communication. Has become rarer since. See also talk mode.

Node:Halloween Documents, Next:hammer, Previous:hakspek, Up:= H =

Halloween Documents n.

A pair of Microsoft internal strategy memoranda leaked to ESR in late 1998 that confirmed everybody's paranoia about the current Evil Empire. These documents praised the technical excellence of Linux and outlined a counterstrategy of attempting to lock in customers by "de-commoditizing" Internet protocols and services. They were extensively cited on the Internet and in the press and proved so embarrassing that Microsoft PR barely said a word in public for six months afterwards.

Node:hammer, Next:hamster, Previous:Halloween Documents, Up:= H =

hammer vt.

Commonwealth hackish syn. for bang on.

Node:hamster, Next:HAND, Previous:hammer, Up:= H =

hamster n.

1. [Fairchild] A particularly slick little piece of code that does one thing well; a small, self-contained hack. The image is of a hamster happily spinning its exercise wheel. 2. A tailless mouse; that is, one with an infrared link to a receiver on the machine, as opposed to the conventional cable. 3. [UK] Any item of hardware made by Amstrad, a company famous for its cheap plastic PC-almost-compatibles.

Node:HAND, Next:hand cruft, Previous:hamster, Up:= H =

HAND //

[Usenet: very common] Abbreviation: Have A Nice Day. Typically used to close a Usenet posting, but also used to informally close emails; often preceded by HTH.

Node:hand cruft, Next:hand-hacking, Previous:HAND, Up:= H =

hand cruft vt.

[pun on `hand craft'] See cruft, sense 3.

Node:hand-hacking, Next:hand-roll, Previous:hand cruft, Up:= H =

hand-hacking n.

1. [rare] The practice of translating hot spots from an HLL into hand-tuned assembler, as opposed to trying to coerce the compiler into generating better code. Both the term and the practice are becoming uncommon. See tune, bum, by hand; syn. with v. cruft. 2. [common] More generally, manual construction or patching of data sets that would normally be generated by a translation utility and interpreted by another program, and aren't really designed to be read or modified by humans.

Node:hand-roll, Next:handle, Previous:hand-hacking, Up:= H =

hand-roll v.

[from obs. mainstream slang `hand-rolled' in opposition to `ready-made', referring to cigarettes] To perform a normally automated software installation or configuration process by hand; implies that the normal process failed due to bugs in the configurator or was defeated by something exceptional in the local environment. "The worst thing about being a gateway between four different nets is having to hand-roll a new sendmail configuration every time any of them upgrades."

Node:handle, Next:handshaking, Previous:hand-roll, Up:= H =

handle n.

1. [from CB slang] An electronic pseudonym; a `nom de guerre' intended to conceal the user's true identity. Network and BBS handles function as the same sort of simultaneous concealment and display one finds on Citizen's Band radio, from which the term was adopted. Use of grandiose handles is characteristic of warez d00dz, crackers, weenies, spods, and other lower forms of network life; true hackers travel on their own reputations rather than invented legendry. Compare nick, screen name. 2. A magic cookie, often in the form of a numeric index into some array somewhere, through which you can manipulate an object like a file or window. The form `file handle' is especially common. 3. [Mac] A pointer to a pointer to dynamically-allocated memory; the extra level of indirection allows on-the-fly memory compaction (to cut down on fragmentation) or aging out of unused resources, with minimal impact on the (possibly multiple) parts of the larger program containing references to the allocated memory. Compare snap (to snap a handle would defeat its purpose); see also aliasing bug, dangling pointer.

Node:handshaking, Next:handwave, Previous:handle, Up:= H =

handshaking n.

[very common] Hardware or software activity designed to start or keep two machines or programs in synchronization as they do protocol. Often applied to human activity; thus, a hacker might watch two people in conversation nodding their heads to indicate that they have heard each others' points and say "Oh, they're handshaking!". See also protocol.

Node:handwave, Next:hang, Previous:handshaking, Up:= H =

handwave

[poss. from gestures characteristic of stage magicians] 1. v. To gloss over a complex point; to distract a listener; to support a (possibly actually valid) point with blatantly faulty logic. 2. n. The act of handwaving. "Boy, what a handwave!"

If someone starts a sentence with "Clearly..." or "Obviously..." or "It is self-evident that...", it is a good bet he is about to handwave (alternatively, use of these constructions in a sarcastic tone before a paraphrase of someone else's argument suggests that it is a handwave). The theory behind this term is that if you wave your hands at the right moment, the listener may be sufficiently distracted to not notice that what you have said is bogus. Failing that, if a listener does object, you might try to dismiss the objection with a wave of your hand.

The use of this word is often accompanied by gestures: both hands up, palms forward, swinging the hands in a vertical plane pivoting at the elbows and/or shoulders (depending on the magnitude of the handwave); alternatively, holding the forearms in one position while rotating the hands at the wrist to make them flutter. In context, the gestures alone can suffice as a remark; if a speaker makes an outrageously unsupported assumption, you might simply wave your hands in this way, as an accusation, far more eloquent than words could express, that his logic is faulty.

Node:hang, Next:Hanlon's Razor, Previous:handwave, Up:= H =

hang v.

1. [very common] To wait for an event that will never occur. "The system is hanging because it can't read from the crashed drive". See wedged, hung. 2. To wait for some event to occur; to hang around until something happens. "The program displays a menu and then hangs until you type a character." Compare block. 3. To attach a peripheral device, esp. in the construction `hang off': "We're going to hang another tape drive off the file server." Implies a device attached with cables, rather than something that is strictly inside the machine's chassis.

Node:Hanlon's Razor, Next:happily, Previous:hang, Up:= H =

Hanlon's Razor prov.

A corollary of Finagle's Law, similar to Occam's Razor, that reads "Never attribute to malice that which can be adequately explained by stupidity." The derivation of the Hanlon eponym is not definitely known, but a very similar remark ("You have attributed conditions to villainy that simply result from stupidity.") appears in "Logic of Empire", a classic 1941 SF story by Robert A. Heinlein, who calls it the `devil theory' of sociology. Heinlein's popularity in the hacker culture makes plausible the supposition that `Hanlon' is derived from `Heinlein' by phonetic corruption. A similar epigram has been attributed to William James, but Heinlein more probably got the idea from Alfred Korzybski and other practitioners of General Semantics. Quoted here because it seems to be a particular favorite of hackers, often showing up in sig blocks, fortune cookie files and the login banners of BBS systems and commercial networks. This probably reflects the hacker's daily experience of environments created by well-intentioned but short-sighted people. Compare Sturgeon's Law, Ninety-Ninety Rule.

Node:happily, Next:haque, Previous:Hanlon's Razor, Up:= H =

happily adv.

Of software, used to emphasize that a program is unaware of some important fact about its environment, either because it has been fooled into believing a lie, or because it doesn't care. The sense of `happy' here is not that of elation, but rather that of blissful ignorance. "The program continues to run, happily unaware that its output is going to /dev/null." Also used to suggest that a program or device would really rather be doing something destructive, and is being given an opportunity to do so. "If you enter an O here instead of a zero, the program will happily erase all your data." Neverheless, use of this term implies a basically benign attitude towards the program: It didn't mean any harm, it was just eager to do its job. We'd like to be angry at it but we shouldn't, we should try to understand it instead. The adjective "cheerfully" is often used in exactly the same way.

Node:haque, Next:hard boot, Previous:happily, Up:= H =

haque /hak/ n.

[Usenet] Variant spelling of hack, used only for the noun form and connoting an elegant hack. that is a hack in sense 2.

Node:hard boot, Next:hardcoded, Previous:haque, Up:= H =

hard boot n.

See boot.

Node:hardcoded, Next:hardwarily, Previous:hard boot, Up:= H =

hardcoded adj.

1. [common] Said of data inserted directly into a program, where it cannot be easily modified, as opposed to data in some profile, resource (see de-rezz sense 2), or environment variable that a user or hacker can easily modify. 2. In C, this is esp. applied to use of a literal instead of a #define macro (see magic number).

Node:hardwarily, Next:hardwired, Previous:hardcoded, Up:= H =

hardwarily /hard-weir'*-lee/ adv.

In a way pertaining to hardware. "The system is hardwarily unreliable." The adjective `hardwary' is not traditionally used, though it has recently been reported from the U.K. See softwarily.

Node:hardwired, Next:has the X nature, Previous:hardwarily, Up:= H =

hardwired adj.

1. In software, syn. for hardcoded. 2. By extension, anything that is not modifiable, especially in the sense of customizable to one's particular needs or tastes.

Node:has the X nature, Next:hash bucket, Previous:hardwired, Up:= H =

has the X nature

[seems to derive from Zen Buddhist koans of the form "Does an X have the Buddha-nature?"] adj. Common hacker construction for `is an X', used for humorous emphasis. "Anyone who can't even use a program with on-screen help embedded in it truly has the loser nature!" See also the X that can be Y is not the true X. See also mu.

Node:hash bucket, Next:hash collision, Previous:has the X nature, Up:= H =

hash bucket n.

A notional receptacle, a set of which might be used to apportion data items for sorting or lookup purposes. When you look up a name in the phone book (for example), you typically hash it by extracting its first letter; the hash buckets are the alphabetically ordered letter sections. This term is used as techspeak with respect to code that uses actual hash functions; in jargon, it is used for human associative memory as well. Thus, two things `in the same hash bucket' are more difficult to discriminate, and may be confused. "If you hash English words only by length, you get too many common grammar words in the first couple of hash buckets." Compare hash collision.

Node:hash collision, Next:hat, Previous:hash bucket, Up:= H =

hash collision n.

[from the techspeak] (var. `hash clash') When used of people, signifies a confusion in associative memory or imagination, especially a persistent one (see thinko). True story: One of us [ESR] was once on the phone with a friend about to move out to Berkeley. When asked what he expected Berkeley to be like, the friend replied: "Well, I have this mental picture of naked women throwing Molotov cocktails, but I think that's just a collision in my hash tables." Compare hash bucket.

Node:hat, Next:HCF, Previous:hash collision, Up:= H =

hat n.

Common (spoken) name for the circumflex (`^', ASCII 1011110) character. See ASCII for other synonyms.

Node:HCF, Next:heads down, Previous:hat, Up:= H =

HCF /H-C-F/ n.

Mnemonic for `Halt and Catch Fire', any of several undocumented and semi-mythical machine instructions with destructive side-effects, supposedly included for test purposes on several well-known architectures going as far back as the IBM 360. The MC6800 microprocessor was the first for which an HCF opcode became widely known. This instruction caused the processor to toggle a subset of the bus lines as rapidly as it could; in some configurations this could actually cause lines to burn up. Compare killer poke.

Node:heads down, Next:heartbeat, Previous:HCF, Up:= H =

heads down [Sun] adj.

Concentrating, usually so heavily and for so long that everything outside the focus area is missed. See also hack mode and larval stage, although this mode is hardly confined to fledgling hackers.

Node:heartbeat, Next:heatseeker, Previous:heads down, Up:= H =

heartbeat n.

1. The signal emitted by a Level 2 Ethernet transceiver at the end of every packet to show that the collision-detection circuit is still connected. 2. A periodic synchronization signal used by software or hardware, such as a bus clock or a periodic interrupt. 3. The `natural' oscillation frequency of a computer's clock crystal, before frequency division down to the machine's clock rate. 4. A signal emitted at regular intervals by software to demonstrate that it is still alive. Sometimes hardware is designed to reboot the machine if it stops hearing a heartbeat. See also breath-of-life packet.

Node:heatseeker, Next:heavy metal, Previous:heartbeat, Up:= H =

heatseeker n.

[IBM] A customer who can be relied upon to buy, without fail, the latest version of an existing product (not quite the same as a member of the lunatic fringe). A 1993 example of a heatseeker was someone who, owning a 286 PC and Windows 3.0, went out and bought Windows 3.1 (which offers no worthwhile benefits unless you have a 386). If all customers were heatseekers, vast amounts of money could be made by just fixing some of the bugs in each release (n) and selling it to them as release (n+1). Microsoft in fact seems to have mastered this technique.

Node:heavy metal, Next:heavy wizardry, Previous:heatseeker, Up:= H =

heavy metal n.

[Cambridge] Syn. big iron.

Node:heavy wizardry, Next:heavyweight, Previous:heavy metal, Up:= H =

heavy wizardry n.

Code or designs that trade on a particularly intimate knowledge or experience of a particular operating system or language or complex application interface. Distinguished from deep magic, which trades more on arcane theoretical knowledge. Writing device drivers is heavy wizardry; so is interfacing to X (sense 2) without a toolkit. Esp. found in source-code comments of the form "Heavy wizardry begins here". Compare voodoo programming.

Node:heavyweight, Next:heisenbug, Previous:heavy wizardry, Up:= H =

heavyweight adj.

[common] High-overhead; baroque; code-intensive; featureful, but costly. Esp. used of communication protocols, language designs, and any sort of implementation in which maximum generality and/or ease of implementation has been pushed at the expense of mundane considerations such as speed, memory utilization, and startup time. EMACS is a heavyweight editor; X is an extremely heavyweight window system. This term isn't pejorative, but one hacker's heavyweight is another's elephantine and a third's monstrosity. Oppose `lightweight'. Usage: now borders on techspeak, especially in the compound `heavyweight process'.

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heisenbug /hi:'zen-buhg/ n.

[from Heisenberg's Uncertainty Principle in quantum physics] A bug that disappears or alters its behavior when one attempts to probe or isolate it. (This usage is not even particularly fanciful; the use of a debugger sometimes alters a program's operating environment significantly enough that buggy code, such as that which relies on the values of uninitialized memory, behaves quite differently.) Antonym of Bohr bug; see also mandelbug, schroedinbug. In C, nine out of ten heisenbugs result from uninitialized auto variables, fandango on core phenomena (esp. lossage related to corruption of the malloc arena) or errors that smash the stack.

Node:Helen Keller mode, Next:hello sailor!, Previous:heisenbug, Up:= H =

Helen Keller mode n.

1. State of a hardware or software system that is deaf, dumb, and blind, i.e., accepting no input and generating no output, usually due to an infinite loop or some other excursion into deep space. (Unfair to the real Helen Keller, whose success at learning speech was triumphant.) See also go flatline, catatonic. 2. On IBM PCs under DOS, refers to a specific failure mode in which a screen saver has kicked in over an ill-behaved application which bypasses the very interrupts the screen saver watches for activity. Your choices are to try to get from the program's current state through a successful save-and-exit without being able to see what you're doing, or to re-boot the machine. This isn't (strictly speaking) a crash.

Node:hello sailor!, Next:hello wall!, Previous:Helen Keller mode, Up:= H =

hello sailor! interj.

Occasional West Coast equivalent of hello world; seems to have originated at SAIL, later associated with the game Zork (which also included "hello, aviator" and "hello, implementor"). Originally from the traditional hooker's greeting to a swabbie fresh off the boat, of course. The standard response is "Nothing happens here."; of all the Zork/Dungeon games, only in Infocom's Zork 3 is "Hello, Sailor" actually useful (excluding the unique situation where _knowing_ this fact is important in Dungeon...).

Node:hello wall!, Next:hello world, Previous:hello sailor!, Up:= H =

hello, wall! excl.

See wall.

Node:hello world, Next:hex, Previous:hello wall!, Up:= H =

hello world interj.

1. The canonical minimal test message in the C/Unix universe. 2. Any of the minimal programs that emit this message. Traditionally, the first program a C coder is supposed to write in a new environment is one that just prints "hello, world" to standard output (and indeed it is the first example program in K&R). Environments that generate an unreasonably large executable for this trivial test or which require a hairy compiler-linker invocation to generate it are considered to lose (see X). 3. Greeting uttered by a hacker making an entrance or requesting information from anyone present. "Hello, world! Is the LAN back up yet?"

Node:hex, Next:hexadecimal, Previous:hello world, Up:= H =

hex n.

1. Short for hexadecimal, base 16. 2. A 6-pack of anything (compare quad, sense 2). Neither usage has anything to do with magic or black art, though the pun is appreciated and occasionally used by hackers. True story: As a joke, some hackers once offered some surplus ICs for sale to be worn as protective amulets against hostile magic. The chips were, of course, hex inverters.

Node:hexadecimal, Next:hexit, Previous:hex, Up:= H =

hexadecimal n.

Base 16. Coined in the early 1960s to replace earlier `sexadecimal', which was too racy and amusing for stuffy IBM, and later adopted by the rest of the industry.

Actually, neither term is etymologically pure. If we take `binary' to be paradigmatic, the most etymologically correct term for base 10, for example, is `denary', which comes from `deni' (ten at a time, ten each), a Latin `distributive' number; the corresponding term for base-16 would be something like `sendenary'. `Decimal' is from an ordinal number; the corresponding prefix for 6 would imply something like `sextidecimal'. The `sexa-' prefix is Latin but incorrect in this context, and `hexa-' is Greek. The word `octal' is similarly incorrect; a correct form would be `octaval' (to go with decimal), or `octonary' (to go with binary). If anyone ever implements a base-3 computer, computer scientists will be faced with the unprecedented dilemma of a choice between two correct forms; both `ternary' and `trinary' have a claim to this throne.

Node:hexit, Next:HHOK, Previous:hexadecimal, Up:= H =

hexit /hek'sit/ n.

A hexadecimal digit (0-9, and A-F or a-f). Used by people who claim that there are only ten digits, dammit; sixteen-fingered human beings are rather rare, despite what some keyboard designs might seem to imply (see space-cadet keyboard).

Node:HHOK, Next:HHOS, Previous:hexit, Up:= H =

HHOK

See ha ha only serious.

Node:HHOS, Next:hidden flag, Previous:HHOK, Up:= H =

HHOS

See ha ha only serious.

Node:hidden flag, Next:high bit, Previous:HHOS, Up:= H =

hidden flag n.

[scientific computation] An extra option added to a routine without changing the calling sequence. For example, instead of adding an explicit input variable to instruct a routine to give extra diagnostic output, the programmer might just add a test for some otherwise meaningless feature of the existing inputs, such as a negative mass. The use of hidden flags can make a program very hard to debug and understand, but is all too common wherever programs are hacked on in a hurry.

Node:high bit, Next:high moby, Previous:hidden flag, Up:= H =

high bit n.

[from `high-order bit'] 1. The most significant bit in a byte. 2. [common] By extension, the most significant part of something other than a data byte: "Spare me the whole saga, just give me the high bit." See also meta bit, hobbit, dread high-bit disease, and compare the mainstream slang `bottom line'.

Node:high moby, Next:highly, Previous:high bit, Up:= H =

high moby /hi:' mohb'ee/ n.

The high half of a 512K PDP-10's physical address space; the other half was of course the low moby. This usage has been generalized in a way that has outlasted the PDP-10; for example, at the 1990 Washington D.C. Area Science Fiction Conclave (Disclave), when a miscommunication resulted in two separate wakes being held in commemoration of the shutdown of MIT's last ITS machines, the one on the upper floor was dubbed the `high moby' and the other the `low moby'. All parties involved grokked this instantly. See moby.

Node:highly, Next:hing, Previous:high moby, Up:= H =

highly adv.

[scientific computation] The preferred modifier for overstating an understatement. As in: `highly nonoptimal', the worst possible way to do something; `highly nontrivial', either impossible or requiring a major research project; `highly nonlinear', completely erratic and unpredictable; `highly nontechnical', drivel written for lusers, oversimplified to the point of being misleading or incorrect (compare drool-proof paper). In other computing cultures, postfixing of in the extreme might be preferred.

Node:hing, Next:hired gun, Previous:highly, Up:= H =

hing // n.

[IRC] Fortuitous typo for `hint', now in wide intentional use among players of initgame. Compare newsfroup, filk.

Node:hired gun, Next:hirsute, Previous:hing, Up:= H =

hired gun n.

A contract programmer, as opposed to a full-time staff member. All the connotations of this term suggested by innumerable spaghetti Westerns are intentional.

Node:hirsute, Next:HLL, Previous:hired gun, Up:= H =

hirsute adj.

Occasionally used humorously as a synonym for hairy.

Node:HLL, Next:hoarding, Previous:hirsute, Up:= H =

HLL /H-L-L/ n.

[High-Level Language (as opposed to assembler)] Found primarily in email and news rather than speech. Rarely, the variants `VHLL' and `MLL' are found. VHLL stands for `Very-High-Level Language' and is used to describe a bondage-and-discipline language that the speaker happens to like; Prolog and Backus's FP are often called VHLLs. `MLL' stands for `Medium-Level Language' and is sometimes used half-jokingly to describe C, alluding to its `structured-assembler' image. See also languages of choice.

Node:hoarding, Next:hobbit, Previous:HLL, Up:= H =

hoarding n.

See software hoarding.

Node:hobbit, Next:hog, Previous:hoarding, Up:= H =

hobbit n.

1. [rare] The High Order BIT of a byte; same as the meta bit or high bit. 2. The non-ITS name of [email protected] (*Hobbit*), master of lasers.

Node:hog, Next:hole, Previous:hobbit, Up:= H =

hog n.,vt.

1. Favored term to describe programs or hardware that seem to eat far more than their share of a system's resources, esp. those which noticeably degrade interactive response. Not used of programs that are simply extremely large or complex or that are merely painfully slow themselves. More often than not encountered in qualified forms, e.g., `memory hog', `core hog', `hog the processor', `hog the disk'. "A controller that never gives up the I/O bus gets killed after the bus-hog timer expires." 2. Also said of people who use more than their fair share of resources (particularly disk, where it seems that 10% of the people use 90% of the disk, no matter how big the disk is or how many people use it). Of course, once disk hogs fill up one filesystem, they typically find some other new one to infect, claiming to the sysadmin that they have an important new project to complete.

Node:hole, Next:hollised, Previous:hog, Up:= H =

hole n.

A region in an otherwise flat entity which is not actually present. For example, some Unix filesystems can store large files with holes so that unused regions of the file are never actually stored on disk. (In techspeak, these are referred to as `sparse' files.) As another example, the region of memory in IBM PCs reserved for memory-mapped I/O devices which may not actually be present is called `the I/O hole', since memory-management systems must skip over this area when filling user requests for memory.

Node:hollised, Next:holy wars, Previous:hole, Up:= H =

hollised /hol'ist/ adj.

[Usenet: _sci.space_] To be hollised is to have been ordered by one's employer not to post any even remotely job-related material to Usenet (or, by extension, to other Internet media). The original and most notorious case of this involved one Ken Hollis, a Lockheed employee and space-program enthusiast who posted publicly available material on access to Space Shuttle launches to _sci.space_. He was gagged under threat of being fired in 1994 at the behest of NASA public-relations officers. The result was, of course, a huge publicity black eye for NASA. Nevertheless several other NASA contractor employees were subsequently hollised for similar activities. Use of this term carries the strong connotation that the persons doing the gagging are bureaucratic idiots blinded to their own best interests by territorial reflexes.

Node:holy wars, Next:home box, Previous:hollised, Up:= H =

holy wars n.

[from Usenet, but may predate it; common] n. flame wars over religious issues. The paper by Danny Cohen that popularized the terms big-endian and little-endian in connection with the LSB-first/MSB-first controversy was entitled "On Holy Wars and a Plea for Peace".

Great holy wars of the past have included ITS vs. Unix, Unix vs. VMS, BSD Unix vs. USG Unix, C vs. Pascal, C vs. FORTRAN, etc. In the year 2000, popular favorites of the day are KDE vs, GNOME, vim vs. elvis, Linux vs. [Free|Net|Open]BSD. Hardy perennials include EMACS vs. vi, my personal computer vs. everyone else's personal computer, ad nauseam. The characteristic that distinguishes holy wars from normal technical disputes is that in a holy war most of the participants spend their time trying to pass off personal value choices and cultural attachments as objective technical evaluations. This happens precisely because in a true holy war, the actual substantive differences between the sides are relatively minor. See also theology.

Node:home box, Next:home machine, Previous:holy wars, Up:= H =

home box n.

A hacker's personal machine, especially one he or she owns. "Yeah? Well, my home box runs a full 4.4 BSD, so there!"

Node:home machine, Next:home page, Previous:home box, Up:= H =

home machine n.

1. Syn. home box. 2. The machine that receives your email. These senses might be distinct, for example, for a hacker who owns one computer at home, but reads email at work.

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home page n.

1. One's personal billboard on the World Wide Web. The term `home page' is perhaps a bit misleading because home directories and physical homes in RL are private, but home pages are designed to be very public. 2. By extension, a WWW repository for information and links related to a project or organization. Compare home box.

Node:honey pot, Next:hook, Previous:home page, Up:= H =

honey pot n.

A box designed to attract crackers so that they can be observed in action. It is usually well isolated from the rest of the network, but has extensive logging (usually network layer, on a different machine). Different from an iron box in that it's purpose is to attract, not merely observe. Sometimes, it is also a defensive network security tactic - you set up an easy-to-crack box so that your real servers don't get messed with. The concept was presented in Cheswick & Bellovin's book "Firewalls and Internet Security".

Node:hook, Next:hop, Previous:honey pot, Up:= H =

hook n.

A software or hardware feature included in order to simplify later additions or changes by a user. For example, a simple program that prints numbers might always print them in base 10, but a more flexible version would let a variable determine what base to use; setting the variable to 5 would make the program print numbers in base 5. The variable is a simple hook. An even more flexible program might examine the variable and treat a value of 16 or less as the base to use, but treat any other number as the address of a user-supplied routine for printing a number. This is a hairy but powerful hook; one can then write a routine to print numbers as Roman numerals, say, or as Hebrew characters, and plug it into the program through the hook. Often the difference between a good program and a superb one is that the latter has useful hooks in judiciously chosen places. Both may do the original job about equally well, but the one with the hooks is much more flexible for future expansion of capabilities (EMACS, for example, is all hooks). The term `user exit' is synonymous but much more formal and less hackish.

Node:hop, Next:hose, Previous:hook, Up:= H =

hop

1. n. [common] One file transmission in a series required to get a file from point A to point B on a store-and-forward network. On such networks (including UUCPNET and FidoNet), an important inter-machine metric is the number of hops in the shortest path between them, which can be more significant than their geographical separation. See bang path. 2. v. [rare] To log in to a remote machine, esp. via rlogin or telnet. "I'll hop over to foovax to FTP that."

Node:hose, Next:hosed, Previous:hop, Up:= H =

hose

1. vt. [common] To make non-functional or greatly degraded in performance. "That big ray-tracing program really hoses the system." See hosed. 2. n. A narrow channel through which data flows under pressure. Generally denotes data paths that represent performance bottlenecks. 3. n. Cabling, especially thick Ethernet cable. This is sometimes called `bit hose' or `hosery' (play on `hosiery') or `etherhose'. See also washing machine.

Node:hosed, Next:hot chat, Previous:hose, Up:= H =

hosed adj.

Same as down. Used primarily by Unix hackers. Humorous: also implies a condition thought to be relatively easy to reverse. Probably derived from the Canadian slang `hoser' popularized by the Bob and Doug Mackenzie skits on SCTV, but this usage predated SCTV by years in hackerdom (it was certainly already live at CMU in the 1970s). See hose. It is also widely used of people in the mainstream sense of `in an extremely unfortunate situation'.

Once upon a time, a Cray that had been experiencing periodic difficulties crashed, and it was announced to have been hosed. It was discovered that the crash was due to the disconnection of some coolant hoses. The problem was corrected, and users were then assured that everything was OK because the system had been rehosed. See also dehose.

Node:hot chat, Next:hot spot, Previous:hosed, Up:= H =

hot chat n.

Sexually explicit one-on-one chat. See teledildonics.

Node:hot spot, Next:hotlink, Previous:hot chat, Up:= H =

hot spot n.

1. [primarily used by C/Unix programmers, but spreading] It is received wisdom that in most programs, less than 10% of the code eats 90% of the execution time; if one were to graph instruction visits versus code addresses, one would typically see a few huge spikes amidst a lot of low-level noise. Such spikes are called `hot spots' and are good candidates for heavy optimization or hand-hacking. The term is especially used of tight loops and recursions in the code's central algorithm, as opposed to (say) initial set-up costs or large but infrequent I/O operations. See tune, bum, hand-hacking. 2. The active location of a cursor on a bit-map display. "Put the mouse's hot spot on the `ON' widget and click the left button." 3. A screen region that is sensitive to mouse gestures, which trigger some action. World Wide Web pages now provide the canonical examples; WWW browsers present hypertext links as hot spots which, when clicked on, point the browser at another document (these are specifically called hotlinks). 4. In a massively parallel computer with shared memory, the one location that all 10,000 processors are trying to read or write at once (perhaps because they are all doing a busy-wait on the same lock). 5. More generally, any place in a hardware design that turns into a performance bottleneck due to resource contention.

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hotlink /hot'link/ n.

A hot spot on a World Wide Web page; an area, which, when clicked or selected, chases a URL. Also spelled `hot link'. Use of this term focuses on the link's role as an immediate part of your display, as opposed to the timeless sense of logical connection suggested by web pointer. Your screen shows hotlinks but your document has web pointers, not (in normal usage) the other way around.

Node:house wizard, Next:HP-SUX, Previous:hotlink, Up:= H =

house wizard n.

[prob. from ad-agency tradetalk, `house freak'] A hacker occupying a technical-specialist, R&D, or systems position at a commercial shop. A really effective house wizard can have influence out of all proportion to his/her ostensible rank and still not have to wear a suit. Used esp. of Unix wizards. The term `house guru' is equivalent.

Node:HP-SUX, Next:HTH, Previous:house wizard, Up:= H =

HP-SUX /H-P suhks/ n.

Unflattering hackerism for HP-UX, Hewlett-Packard's Unix port, which features some truly unique bogosities in the filesystem internals and elsewhere (these occasionally create portability problems). HP-UX is often referred to as `hockey-pux' inside HP, and one respondent claims that the proper pronunciation is /H-P ukkkhhhh/ as though one were about to spit. Another such alternate spelling and pronunciation is "H-PUX" /H-puhks/. Hackers at HP/Apollo (the former Apollo Computers which was swallowed by HP in 1989) have been heard to complain that Mr. Packard should have pushed to have his name first, if for no other reason than the greater eloquence of the resulting acronym. Compare AIDX, buglix. See also Nominal Semidestructor, Telerat, ScumOS, sun-stools, Slowlaris.

Node:HTH, Next:huff, Previous:HP-SUX, Up:= H =

HTH //

[Usenet: very common] Abbreviation: Hope This Helps (e.g. following a response to a technical question). Often used just before HAND. See also YHBT.

Node:huff, Next:humma, Previous:HTH, Up:= H =

huff v.

To compress data using a Huffman code. Various programs that use such methods have been called `HUFF' or some variant thereof. Oppose puff. Compare crunch, compress.

Node:humma, Next:hung, Previous:huff, Up:= H =

humma // excl.

A filler word used on various `chat' and `talk' programs when you had nothing to say but felt that it was important to say something. The word apparently originated (at least with this definition) on the MECC Timeshare System (MTS, a now-defunct educational time-sharing system running in Minnesota during the 1970s and the early 1980s) but was later sighted on early Unix systems. Compare the U.K's wibble.

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hung adj.

[from `hung up'; common] Equivalent to wedged, but more common at Unix/C sites. Not generally used of people. Syn. with locked up, wedged; compare hosed. See also hang. A hung state is distinguished from crashed or down, where the program or system is also unusable but because it is not running rather than because it is waiting for something. However, the recovery from both situations is often the same. It is also distinguished from the similar but more drastic state wedged - hung software can be woken up with easy things like interrupt keys, but wedged will need a kill -9 or even reboot.

Node:hungry puppy, Next:hungus, Previous:hung, Up:= H =

hungry puppy n.

Syn. slopsucker.

Node:hungus, Next:hyperspace, Previous:hungry puppy, Up:= H =

hungus /huhng'g*s/ adj.

[perhaps related to slang `humongous'] Large, unwieldy, usually unmanageable. "TCP is a hungus piece of code." "This is a hungus set of modifications." The Infocom text adventure game "Beyond Zork" included two monsters called hunguses.

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hyperspace /hi:'per-spays/ n.

A memory location that is far away from where the program counter should be pointing, especially a place that is inaccessible because it is not even mapped in by the virtual-memory system. "Another core dump -- looks like the program jumped off to hyperspace somehow." (Compare jump off into never-never land.) This usage is from the SF notion of a spaceship jumping `into hyperspace', that is, taking a shortcut through higher-dimensional space -- in other words, bypassing this universe. The variant `east hyperspace' is recorded among CMU and Bliss hackers.

Node:hysterical reasons, Next:I didn't change anything!, Previous:hyperspace, Up:= H =

hysterical reasons n.

(also `hysterical raisins') A variant on the stock phrase "for historical reasons", indicating specifically that something must be done in some stupid way for backwards compatibility, and moreover that the feature it must be compatible with was the result of a bad design in the first place. "All IBM PC video adapters have to support MDA text mode for hysterical reasons." Compare bug-for-bug compatible.

Node:= I =, Next:= J =, Previous:= H =, Up:The Jargon Lexicon

= I =

I didn't change anything!:

I see no X here.:

IANAL:

IBM:

IBM discount:

ICBM address:

ice:

ID10T error:

idempotent:

IDP:

If you want X you know where to find it.:

ifdef out:

IIRC:

ill-behaved:

IMHO:

Imminent Death Of The Net Predicted!:

in the extreme:

inc:

incantation:

include:

include war:

indent style:

index of X:

infant mortality:

infinite:

infinite loop:

Infinite-Monkey Theorem:

infinity:

inflate:

Infocom:

initgame:

insanely great:

installfest:

INTERCAL:

interesting:

Internet:

Internet address:

Internet Death Penalty:

Internet Exploder:

Internet Exploiter:

interrupt:

interrupt list:

interrupts locked out:

intro:

IRC:

iron:

Iron Age:

iron box:

ironmonger:

ISO standard cup of tea:

ISP:

ITS:

IWBNI:

IYFEG:

Node:I didn't change anything!, Next:I see no X here., Previous:hysterical reasons, Up:= I =

I didn't change anything! interj.

An aggrieved cry often heard as bugs manifest during a regression test. The canonical reply to this assertion is "Then it works just the same as it did before, doesn't it?" See also one-line fix. This is also heard from applications programmers trying to blame an obvious applications problem on an unrelated systems software change, for example a divide-by-0 fault after terminals were added to a network. Usually, their statement is found to be false. Upon close questioning, they will admit some major restructuring of the program that shouldn't have broken anything, in their opinion, but which actually hosed the code completely.

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I see no X here.

Hackers (and the interactive computer games they write) traditionally favor this slightly marked usage over other possible equivalents such as "There's no X here!" or "X is missing." or "Where's the X?". This goes back to the original PDP-10 ADVENT, which would respond in this wise if you asked it to do something involving an object not present at your location in the game.

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IANAL //

[Usenet] Abbreviation, "I Am Not A Lawyer". Usually precedes legal advice.

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IBM /I-B-M/

Inferior But Marketable; It's Better Manually; Insidious Black Magic; It's Been Malfunctioning; Incontinent Bowel Movement; and a near-infinite number of even less complimentary expansions, including `International Business Machines'. See TLA. These abbreviations illustrate the considerable antipathy most hackers long felt toward the `industry leader' (see fear and loathing).

What galled hackers about most IBM machines above the PC level wasn't so much that they were underpowered and overpriced (though that does count against them), but that the designs are incredibly archaic, crufty, and elephantine ... and you can't fix them -- source code is locked up tight, and programming tools are expensive, hard to find, and bletcherous to use once you've found them. For many years, before Microsoft, IBM was the company hackers loved to hate.

But everything changes. In the 1980s IBM had its own troubles with Microsoft. In the late 1990s IBM re-invented itself as a services company, began to release open-source software through its AlphaWorks group, and began shipping Linux systems and building ties to the Linux community. To the astonishment of all parties, IBM emerged as a friend of the hacker community

This lexicon includes a number of entries attributed to `IBM'; these derive from some rampantly unofficial jargon lists circulated within IBM's own beleaguered hacker underground.

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IBM discount n.

A price increase. Outside IBM, this derives from the common perception that IBM products are generally overpriced (see clone); inside, it is said to spring from a belief that large numbers of IBM employees living in an area cause prices to rise.

Node:ICBM address, Next:ice, Previous:IBM discount, Up:= I =

ICBM address n.

(Also `missile address') The form used to register a site with the Usenet mapping project, back before the day of pervasive Internet, included a blank for longitude and latitude, preferably to seconds-of-arc accuracy. This was actually used for generating geographically-correct maps of Usenet links on a plotter; however, it became traditional to refer to this as one's `ICBM address' or `missile address', and some people include it in their sig block with that name. (A real missile address would include target elevation.)

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ice n.

[coined by Usenetter Tom Maddox, popularized by William Gibson's cyberpunk SF novels: a contrived acronym for `Intrusion Countermeasure Electronics'] Security software (in Gibson's novels, software that responds to intrusion by attempting to immobilize or even literally kill the intruder). Hence, `icebreaker': a program designed for cracking security on a system.

Neither term is in serious use yet as of early 1999, but many hackers find the metaphor attractive, and each may develop a denotation in the future. In the meantime, the speculative usage could be confused with `ICE', an acronym for "in-circuit emulator".

In ironic reference to the speculative usage, however, some hackers and computer scientists formed ICE (International Cryptographic Experiment) in 1994. ICE is a consortium to promote uniform international access to strong cryptography.

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ID10T error /I-D-ten-T er'*r/

Synonym for PEBKAC, e.g. "The user is being an idiot". Tech-support people passing a problem report to someone higher up the food chain (and presumably better equipped to deal with idiots) may ask the user to convey that there seems to be an I-D-ten-T error. Users never twig.

Node:idempotent, Next:IDP, Previous:ID10T error, Up:= I =

idempotent adj.

[from mathematical techspeak] Acting as if used only once, even if used multiple times. This term is often used with respect to C header files, which contain common definitions and declarations to be included by several source files. If a header file is ever included twice during the same compilation (perhaps due to nested #include files), compilation errors can result unless the header file has protected itself against multiple inclusion; a header file so protected is said to be idempotent. The term can also be used to describe an initialization subroutine that is arranged to perform some critical action exactly once, even if the routine is called several times.

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IDP /I-D-P/ v.,n.

[Usenet] Abbreviation for Internet Death Penalty. Common (probably now more so than the full form), and frequently verbed. Compare UDP.

Node:If you want X you know where to find it., Next:ifdef out, Previous:IDP, Up:= I =

If you want X, you know where to find it.

There is a legend that Dennis Ritchie, inventor of C, once responded to demands for features resembling those of what at the time was a much more popular language by observing "If you want PL/I, you know where to find it." Ever since, this has been hackish standard form for fending off requests to alter a new design to mimic some older (and, by implication, inferior and baroque) one. The case X = Pascal manifests semi-regularly on Usenet's _comp.lang.c_ newsgroup. Indeed, the case X = X has been reported in discussions of graphics software (see X).

Node:ifdef out, Next:IIRC, Previous:If you want X you know where to find it., Up:= I =

ifdef out /if'def owt/ v.

Syn. for condition out, specific to C.

Node:IIRC, Next:ill-behaved, Previous:ifdef out, Up:= I =

IIRC //

Common abbreviation for "If I Recall Correctly".

Node:ill-behaved, Next:IMHO, Previous:IIRC, Up:= I =

ill-behaved adj.

1. [numerical analysis] Said of an algorithm or computational method that tends to blow up because of accumulated roundoff error or poor convergence properties. 2. Software that bypasses the defined OS interfaces to do things (like screen, keyboard, and disk I/O) itself, often in a way that depends on the hardware of the machine it is running on or which is nonportable or incompatible with other pieces of software. In the IBM PC/MS-DOS world, there is a folk theorem (nearly true) to the effect that (owing to gross inadequacies and performance penalties in the OS interface) all interesting applications are ill-behaved. See also bare metal. Oppose well-behaved, compare PC-ism. See mess-dos.

Node:IMHO, Next:Imminent Death Of The Net Predicted!, Previous:ill-behaved, Up:= I =

IMHO // abbrev.

[from SF fandom via Usenet; abbreviation for `In My Humble Opinion'] "IMHO, mixed-case C names should be avoided, as mistyping something in the wrong case can cause hard-to-detect errors -- and they look too Pascalish anyhow." Also seen in variant forms such as IMNSHO (In My Not-So-Humble Opinion) and IMAO (In My Arrogant Opinion).

Node:Imminent Death Of The Net Predicted!, Next:in the extreme, Previous:IMHO, Up:= I =

Imminent Death Of The Net Predicted! prov.

[Usenet] Since Usenet first got off the ground in 1980-81, it has grown exponentially, approximately doubling in size every year. On the other hand, most people feel the signal-to-noise ratio of Usenet has dropped steadily. These trends led, as far back as mid-1983, to predictions of the imminent collapse (or death) of the net. Ten years and numerous doublings later, enough of these gloomy prognostications have been confounded that the phrase "Imminent Death Of The Net Predicted!" has become a running joke, hauled out any time someone grumbles about the S/N ratio or the huge and steadily increasing volume, or the possible loss of a key node or link, or the potential for lawsuits when ignoramuses post copyrighted material, etc., etc., etc.

Node:in the extreme, Next:inc, Previous:Imminent Death Of The Net Predicted!, Up:= I =

in the extreme adj.

A preferred superlative suffix for many hackish terms. See, for example, `obscure in the extreme' under obscure, and compare highly.

Node:inc, Next:incantation, Previous:in the extreme, Up:= I =

inc /ink/ v.

Verbal (and only rarely written) shorthand for _increment_, i.e. `increase by one'. Especially used by assembly programmers, as many assembly languages have an inc mnemonic. Antonym: dec (see DEC).

Node:incantation, Next:include, Previous:inc, Up:= I =

incantation n.

Any particularly arbitrary or obscure command that one must mutter at a system to attain a desired result. Not used of passwords or other explicit security features. Especially used of tricks that are so poorly documented that they must be learned from a wizard. "This compiler normally locates initialized data in the data segment, but if you mutter the right incantation they will be forced into text space."

Node:include, Next:include war, Previous:incantation, Up:= I =

include vt.

[Usenet] 1. To duplicate a portion (or whole) of another's message (typically with attribution to the source) in a reply or followup, for clarifying the context of one's response. See the discussion of inclusion styles under "Hacker Writing Style". 2. [from C] #include <disclaimer.h> has appeared in sig blocks to refer to a notional `standard disclaimer file'.

Node:include war, Next:indent style, Previous:include, Up:= I =

include war n.

Excessive multi-leveled inclusion within a discussion thread, a practice that tends to annoy readers. In a forum with high-traffic newsgroups, such as Usenet, this can lead to flames and the urge to start a kill file.

Node:indent style, Next:index of X, Previous:include war, Up:= I =

indent style n.

[C, C++, and Java programmers] The rules one uses to indent code in a readable fashion. There are four major C indent styles, described below; all have the aim of making it easier for the reader to visually track the scope of control constructs. They have been inherited by C++ and Java, which have C-like syntaxes. The significant variable is the placement of { and } with respect to the statement(s) they enclose and to the guard or controlling statement (if, else, for, while, or do) on the block, if any.

`K&R style' -- Named after Kernighan & Ritchie, because the examples in K&R are formatted this way. Also called `kernel style' because the Unix kernel is written in it, and the `One True Brace Style' (abbrev. 1TBS) by its partisans. In C code, the body is typically indented by eight spaces (or one tab) per level, as shown here. Four spaces are occasionally seen in C, but in C++ and Java four tends to be the rule rather than the exception.

if (<cond>) { <body> }

`Allman style' -- Named for Eric Allman, a Berkeley hacker who wrote a lot of the BSD utilities in it (it is sometimes called `BSD style'). Resembles normal indent style in Pascal and Algol. It is the only style other than K&R in widespread use among Java programmers. Basic indent per level shown here is eight spaces, but four (or sometimes three) spaces are generally preferred by C++ and Java programmers.

if (<cond>) { <body> }