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

several nearly identical copies of the same source tree, e.g., when the only difference is architecture-dependent object files. "Let's freeze the source and then rebuild the FROBOZZ-3 and FROBOZZ-4 link farms." Link farms may also be used to get around restrictions on the number of `-I' (include-file directory) arguments on older C preprocessors. However, they can also get completely out of hand, becoming the filesystem equivalent of {spaghetti code}.

:link-dead: [MUD] adj. Said of a {MUD} character who has frozen in place because of a dropped Internet connection.

:lint: [from UNIX's `lint(1)', named for the bits of fluff it picks from programs] 1. vt. To examine a program closely for style, language usage, and portability problems, esp. if in C, esp. if via use of automated analysis tools, most esp. if the UNIX

utility lint(1)' is used. This term used to be restricted to use oflint(1)' itself, but (judging by references on USENET) it has become a shorthand for {desk check} at some non-UNIX

shops, even in languages other than C. Also as v. {delint}.

n. Excess verbiage in a document, as in "this draft has too much lint".

:lion food: [IBM] n. Middle management or HQ staff (by extension, administrative drones in general). From an old joke about two lions who, escaping from the zoo, split up to increase their chances but agreed to meet after 2 months. When they finally meet, one is skinny and the other overweight. The thin one says: "How did you manage? I ate a human just once and they turned out a small army to chase me --- guns, nets, it was terrible. Since then I've been reduced to eating mice, insects, even grass." The fat one replies: "Well, I hid near an IBM office and ate a manager a day. And nobody even noticed!"

:Lions Book: n. `Source Code and Commentary on UNIX level 6', by John Lions. The two parts of this book contained (1) the entire source listing of the UNIX Version 6 kernel, and (2) a commentary on the source discussing the algorithms. These were circulated internally at the University of New South Wales beginning 1976--77, and were for years after the only detailed kernel documentation available to anyone outside Bell Labs. Because Western Electric wished to maintain trade secret status on the kernel, the Lions book was never formally published and was only supposed to be distributed to affiliates of source licensees. In spite of this, it soon spread by samizdat to a good many of the early UNIX hackers.

:LISP: [from LISt Processing language', but mythically fromLots of Irritating Superfluous Parentheses'] n. The name of AI's mother tongue, a language based on the ideas of (a) variable-length lists and trees as fundamental data types, and (b) the interpretation of code as data and vice-versa. Invented by John McCarthy at MIT in the late 1950s, it is actually older than any other {HLL} still in use except FORTRAN. Accordingly, it has undergone considerable adaptive radiation over the years; modern variants are quite different in detail from the original LISP 1.5.

The dominant HLL among hackers until the early 1980s, LISP now shares the throne with {C}. See {languages of choice}.

All LISP functions and programs are expressions that return values; this, together with the high memory utilization of LISPs, gave rise to Alan Perlis's famous quip (itself a take on an Oscar Wilde quote) that "LISP programmers know the value of everything and the cost of nothing".

One significant application for LISP has been as a proof by example that most newer languages, such as {COBOL} and {Ada}, are full of unnecessary {crock}s. When the {Right Thing} has already been done once, there is no justification for {bogosity} in newer languages.

:literature, the: n. Computer-science journals and other publications, vaguely gestured at to answer a question that the speaker believes is {trivial}. Thus, one might answer an annoying question by saying "It's in the literature." Oppose {Knuth}, which has no connotation of triviality.

:little-endian: adj. Describes a computer architecture in which, within a given 16- or 32-bit word, bytes at lower addresses have lower significance (the word is stored `little-end-first'). The PDP-11 and VAX families of computers and Intel microprocessors and a lot of communications and networking hardware are little-endian.

See {big-endian}, {middle-endian}, {NUXI problem}. The term is sometimes used to describe the ordering of units other than bytes; most often these are bits within a byte.

:live data: n. 1. Data that is written to be interpreted and takes over program flow when triggered by some un-obvious operation, such as viewing it. One use of such hacks is to break security. For example, some smart terminals have commands that allow one to download strings to program keys; this can be used to write live data that, when listed to the terminal, infects it with a security-breaking {virus} that is triggered the next time a hapless user strikes that key. For another, there are some well-known bugs in {vi} that allow certain texts to send arbitrary commands back to the machine when they are simply viewed.

In C code, data that includes pointers to function {hook}s (executable code). 3. An object, such as a {trampoline}, that is constructed on the fly by a program and intended to be executed as code. 4. Actual real-world data, as opposed to `test data'.

For example, "I think I have the record deletion module finished." "Have you tried it out on live data?" It usually carries the connotation that live data is more fragile and must not be corrupted, else bad things will happen. So a possible alternate response to the above claim might be: "Well, make sure it works perfectly before we throw live data at it." The implication here is that record deletion is something pretty significant, and a haywire record-deletion module running amok on live data would cause great harm and probably require restoring from backups.

:Live Free Or Die!: imp. 1. The state motto of New Hampshire, which appears on that state's automobile license plates. 2. A slogan associated with UNIX in the romantic days when UNIX aficionados saw themselves as a tiny, beleaguered underground tilting against the windmills of industry. The "free" referred specifically to freedom from the {fascist} design philosophies and crufty misfeatures common on commercial operating systems. Armando Stettner, one of the early UNIX developers, used to give out fake license plates bearing this motto under a large UNIX, all in New Hampshire colors of green and white. These are now valued collector's items.

:livelock: /li:v'lok/ n. A situation in which some critical stage of a task is unable to finish because its clients perpetually create more work for it to do after they have been serviced but before it can clear its queue. Differs from {deadlock} in that the process is not blocked or waiting for anything, but has a virtually infinite amount of work to do and can never catch up.

:liveware: /li:v'weir/ n. 1. Synonym for {wetware}. Less common. 2. [Cambridge] Vermin. "Waiter, there's some liveware in my salad..."

:lobotomy: n. 1. What a hacker subjected to formal management training is said to have undergone. At IBM and elsewhere this term is used by both hackers and low-level management; the latter doubtless intend it as a joke. 2. The act of removing the processor from a microcomputer in order to replace or upgrade it.

Some very cheap {clone} systems are sold in `lobotomized' form --- everything but the brain.

:locked and loaded: [from military slang for an M-16 rifle with magazine inserted and prepared for firing] adj. Said of a removable disk volume properly prepared for use --- that is, locked into the drive and with the heads loaded. Ironically, because their heads are `loaded' whenever the power is up, this description is never used of {{Winchester}} drives (which are named after a rifle).

:locked up: adj. Syn. for {hung}, {wedged}.

:logic bomb: n. Code surreptitiously inserted in an application or OS that causes it to perform some destructive or security-compromising activity whenever specified conditions are met. Compare {back door}.

:logical: [from the technical term logical device', wherein a physical device is referred to by an arbitrarylogical' name]

adj. Having the role of. If a person (say, Les Earnest at SAIL) who had long held a certain post left and were replaced, the replacement would for a while be known as the `logical' Les Earnest. (This does not imply any judgment on the replacement.) Compare {virtual}.

At Stanford, logical' compass directions denote a coordinate system in whichlogical north' is toward San Francisco, `logical west' is toward the ocean, etc., even though logical north varies between physical (true) north near San Francisco and physical west near San Jose. (The best rule of thumb here is that, by definition, El Camino Real always runs logical north-and-south.) In giving directions, one might say: "To get to Rincon Tarasco restaurant, get onto {El Camino Bignum} going logical north."

Using the word logical' helps to prevent the recipient from worrying about that the fact that the sun is setting almost directly in front of him. The concept is reinforced by North American highways which are almost, but not quite, consistently labeled with logical rather than physical directions. A similar situation exists at MIT: Route 128 (famous for the electronics industry that has grown