: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 from `Lots 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. 2. 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…"