MACROTAPE n. An industry standard reel of tape, as opposed to a MICROTAPE MAGIC adj. 1. As yet unexplained, or too complicated to explain. (Arthur C. Clarke once said that magic was as-yet-not-understood science.) "TTY echoing is controlled by a large number of magic bits." "This routine magically computes the parity of an eight-bit byte in three instructions." 2. (Stanford) A feature not generally publicized which allows something otherwise impossible, or a feature formerly in that category but now unveiled. Example: The keyboard commands which override the screen-hiding features. MARGINAL adj. 1. Extremely small. "A marginal increase in core can decrease GC time drastically." See EPSILON. 2. Of extremely small merit. "This proposed new feature seems rather marginal to me." 3. Of extremely small probability of winning. "The power supply was rather marginal anyway; no wonder it crapped out." 4. MARGINALLY: adv. Slightly. "The ravs here are only marginally better than at Small Eating Place." MICROTAPE n. Occasionally used to mean a DECtape, as opposed to a MACROTAPE. This was the official DEC term for the stuff until someone consed up the word "DECtape". MISFEATURE n. A feature which eventually screws someone, possibly because it is not adequate for a new situation which has evolved. It is not the same as a bug because fixing it involves a gross philosophical change to the structure of the system involved. Often a former feature becomes a misfeature because a tradeoff was made whose parameters subsequently changed (possibly only in the judgment of the implementors). "Well, yeah, it's kind of a misfeature that file names are limited to six characters, but we're stuck with it for now." MOBY [seems to have been in use among model railroad fans years ago. Entered the world of AI with the Fabritek 256K moby memory of MIT-AI. Derived from Melville's "Moby Dick" (some say from "Moby Pickle").] 1. adj. Large, immense, or complex. "A moby frob." 2. n. The maximum address space of a machine, hence 3. n. 256K words, the size of a PDP-10 moby. (The maximum address space means the maximum normally addressable space, as opposed to the amount of physical memory a machine can have. Thus the MIT PDP-10s each have two mobies, usually referred to as the "low moby" (0-777777) and "high moby" (1000000-1777777), or as "moby 0" and "moby 1". MIT-AI has four mobies of address space: moby 2 is the PDP-6 memory, and moby 3 the PDP-11 interface.) In this sense "moby" is often used as a generic unit of either address space (18. bits' worth) or of memory (about a megabyte, or 9/8 megabyte (if one accounts for difference between 32.- and 36.-bit words), or 5/4 megacharacters). 4. A title of address (never of third-person reference), usually used to show admiration, respect, and/or friendliness to a competent hacker. "So, moby Knight, how's the CONS machine doing?" 5. adj. In backgammon, doubles on the dice, as in "moby sixes", "moby ones", etc. MOBY FOO, MOBY WIN, MOBY LOSS: standard emphatic forms. FOBY MOO: a spoonerism due to Greenblatt. MODE n. A general state, usually used with an adjective describing the state. "No time to hack; I'm in thesis mode." Usage: in its jargon sense, MODE is most often said of people, though it is sometimes applied to programs and inanimate objects. "If you're on a TTY, E will switch to non-display mode." In particular, see DAY MODE, NIGHT MODE, and YOYO MODE; also COM MODE, TALK MODE, and GABRIEL MODE. MODULO prep. Except for. From mathematical terminology: one can consider saying that 4=22 "except for the 9's" (4=22 mod 9). "Well, LISP seems to work okay now, modulo that GC bug." MOON n. 1. A celestial object whose phase is very important to hackers. See PHASE OF THE MOON. 2. Dave Moon (MOON@MC). MUMBLAGE n. The topic of one's mumbling (see MUMBLE). "All that mumblage" is used like "all that stuff" when it is not quite clear what it is or how it works, or like "all that crap" when "mumble" is being used as an implicit replacement for obscenities. MUMBLE interj. 1. Said when the correct response is either too complicated to enunciate or the speaker has not thought it out. Often prefaces a longer answer, or indicates a general reluctance to get into a big long discussion. "Well, mumble." 2. Sometimes used as an expression of disagreement. "I think we should buy it." "Mumble!" Common variant: MUMBLE FROTZ. 3. Yet another metasyntactic variable, like FOO. MUNCH (often confused with "mung", q.v.) v. To transform information in a serial fashion, often requiring large amounts of computation. To trace down a data structure. Related to CRUNCH (q.v.), but connotes less pain. MUNCHING SQUARES n. A display hack dating back to the PDP-1, which employs a trivial computation (involving XOR'ing of x-y display coordinates - see HAKMEM items 146-148) to produce an impressive display of moving, growing, and shrinking squares. The hack usually has a parameter (usually taken from toggle switches) which when well-chosen can produce amazing effects. Some of these, discovered recently on the LISP machine, have been christened MUNCHING TRIANGLES, MUNCHING W'S, and MUNCHING MAZES. MUNG (variant: MUNGE) [recursive acronym for Mung Until No Good] v. 1. To make changes to a file, often large-scale, usually irrevocable. Occasionally accidental. See BLT. 2. To destroy, usually accidentally, occasionally maliciously. The system only mungs things maliciously.