:fall through: v. (n. `fallthrough', var. `fall-through') 1. To exit a loop by exhaustion, i.e., by having fulfilled its exit condition rather than via a break or exception condition that exits from the middle of it. This usage appears to be *really* old, dating from the 1940s and 1950s. 2. To fail a test that would have passed control to a subroutine or some other distant portion of code. 3. In C, `fall-through' occurs when the flow of execution in a switch statement reaches a `case' label other than by jumping there from the switch header, passing a point where one would normally expect to find a `break'. A trivial example:
switch (color)
{
case GREEN:
do_green();
break;
case PINK:
do_pink();
/* FALL THROUGH */
case RED:
do_red();
break;
default:
do_blue();
break;
}
The variant spelling `/* FALL THRU */' is also common.
The effect of this code is to `do_green()' when color is `GREEN', `do_red()' when color is `RED', `do_blue()' on any other color other than `PINK', and (and this is the important part) `do_pink()' *and then* `do_red()' when color is `PINK'. Fall-through is {considered harmful} by some, though there are contexts (such as the coding of state machines) in which it is natural; it is generally considered good practice to include a comment highlighting the fall-through where one would normally expect a break.
:fandango on core: [UNIX/C hackers, from the Mexican dance] n. In C, a wild pointer that runs out of bounds, causing a {core dump}, or corrupts the `malloc(3)' {arena} in such a way as to cause mysterious failures later on, is sometimes said to have `done a fandango on core'. On low-end personal machines without an MMU, this can corrupt the OS itself, causing massive lossage. Other frenetic dances such as the rhumba, cha-cha, or watusi, may be substituted. See {aliasing bug}, {precedence lossage}, {smash the stack}, {memory leak}, {memory smash}, {overrun screw}, {core}.
:FAQ list: /F-A-Q list/ or /fak list/ [USENET] n. A compendium of accumulated lore, posted periodically to high-volume newsgroups in an attempt to forestall Frequently Asked Questions. This lexicon itself serves as a good example of a collection of one kind of lore, although it is far too big for a regular posting. Examples: "What is the proper type of NULL?" and "What's that funny name for the `#' character?" are both Frequently Asked Questions. Several extant FAQ lists do (or should) make reference to the Jargon File (the on-line version of this lexicon).
:FAQL: /fa'kl/ n. Syn. {FAQ list}.
:farming: [Adelaide University, Australia] n. What the heads of a disk drive are said to do when they plow little furrows in the magnetic media. Associated with a {crash}. Typically used as follows: "Oh no, the machine has just crashed; I hope the hard drive hasn't gone {farming} again."
:fascist: adj. 1. Said of a computer system with excessive or annoying security barriers, usage limits, or access policies. The implication is that said policies are preventing hackers from getting interesting work done. The variant `fascistic' seems to have been preferred at MIT, poss. by analogy with `touristic' (see {tourist}). 2. In the design of languages and other software tools, `the fascist alternative' is the most restrictive and structured way of capturing a particular function; the implication is that this may be desirable in order to simplify the implementation or provide tighter error checking. Compare {bondage-and-discipline language}, but that term is global rather than local.
:fat electrons: n. Old-time hacker David Cargill's theory on the causation of computer glitches. Your typical electric utility draws its line current out of the big generators with a pair of coil taps located near the top of the dynamo. When the normal tap brushes get dirty, they take them off line to clean up, and use special auxiliary taps on the *bottom* of the coil. Now, this is a problem, because when they do that they get not ordinary or `thin' electrons, but the fat'n'sloppy electrons that are heavier and so settle to the bottom of the generator. These flow down ordinary wires just fine, but when they have to turn a sharp corner (as in an integrated-circuit via) they're apt to get stuck. This is what causes computer glitches. [Fascinating. Obviously, fat electrons must gain mass by {bogon} absorption —- ESR] Compare {bogon}, {magic smoke}.