Search billions of records on
Website logo - Click to go to Home page

Jargon used in computing

= M =

M: [SI] pref. (on units) suff. (on numbers) See {{quantifiers}}.

macdink: /mak'dink/ [from the Apple Macintosh, which is said to encourage such behavior] vt.
   To make many incremental and unnecessary cosmetic changes to a program or file. Often the
   subject of the macdinking would be better off without them. "When I left at 11 P.M. last
   night, he was still macdinking the slides for his presentation."  See also {fritterware}.

machinable: adj. Machine-readable.  Having the {softcopy} nature.

machoflops: /mach'oh-flops/ [pun on `megaflops', a coinage for `millions of FLoating-point
   Operations Per Second'] n. Refers to artificially inflated performance figures often quoted
   by computer manufacturers. Real applications are lucky to get half the quoted speed. See
   {Your mileage may vary}, {benchmark}.

Macintoy: /mak'in-toy/ n. The Apple Macintosh, considered as a {toy}. Less pejorative than

Macintrash: /mak'in-trash`/ n. The Apple Macintosh, as described by a hacker who doesn't
   appreciate being kept away from the *real computer* by the interface. The term {maggotbox}
   has been reported in regular use in the Research Triangle area of North Carolina. Compare
   {Macintoy}. See also {beige toaster}, {WIMP environment}, {drool-proof paper},

macro: /mak'roh/ [techspeak] n. A name (possibly followed by a formal {arg} list) that is
   equated to a text or symbolic expression to which it is to be expanded (possibly with the
   substitution of actual arguments) by a macro expander. This definition can be found in any
   technical dictionary; what those won't tell you is how the hackish connotations of the term
   have changed over time.
   The term `macro' originated in early assemblers, which encouraged the use of macros as a
   structuring and information-hiding device. During the early 1970s, macro assemblers became
   ubiquitous, and sometimes quite as powerful and expensive as {HLL}s, only to fall from
   favour as improving compiler technology marginalized assembler programming (see {languages
   of choice}). Nowadays the term is most often used in connection with the C preprocessor,
   LISP, or one of several special-purpose languages built around a macro-expansion facility
   (such as TeX or UNIX's [nt]roff suite). Indeed, the meaning has drifted enough that the
   collective `macros' is now sometimes used for code in any special-purpose application
   control language (whether or not the language is actually translated by text expansion),
   and for macro-like entities such as the `keyboard macros' supported in some text editors
   (and PC TSR or Macintosh INIT/CDEV keyboard enhancers).

macro-: pref. Large. Opposite of {micro-}. In the mainstream and among other technical
   cultures (for example, medical people) this competes with the prefix {mega-}, but hackers
   tend to restrict the latter to quantification.

macrology: /mak-rol'*-jee/ n. 1. Set of usually complex or crufty macros, e.g., as part of a
   large system written in {LISP}, {TECO}, or (less commonly) assembler. 2. The art and science
   involved in comprehending a macrology in sense 1. Sometimes studying the macrology of a
   system is not unlike archeology, ecology, or {theology}, hence the sound-alike construction.
   See also {boxology}.

macrotape: /ma'kroh-tayp/ n. An industry-standard reel of tape, as opposed to a {microtape}.

maggotbox: /mag'*t-boks/ n. See {Macintrash}.  This is even more derogatory.

magic: adj. 1. As yet unexplained, or too complicated to explain; compare {automagically} and
   (Arthur C.) Clarke's Third Law: "Any sufficiently advanced technology is indistinguishable
   from magic."  "TTY echoing is controlled by a large number of magic bits."  "This routine
   magically computes the parity of an 8-bit byte in three instructions."  2. Characteristic
   of something that works although no one really understands why (this is especially called
   {black magic}).  3. [Stanford] A feature not generally publicized that allows something
   otherwise impossible, or a feature formerly in that category but now unveiled. Compare
   {black magic}, {wizardly}, {deep magic}, {heavy wizardry}.

   For more about hackish `magic', see appendix A.

magic cookie: [UNIX] n. 1. Something passed between routines or programs that enables the
   receiver to perform some operation; a capability ticket or opaque identifier. Especially
   used of small data objects that contain data encoded in a strange or intrinsically machine-
   dependent way. E.g., on non-UNIX OSes with a non-byte-stream model of files, the result of
   `ftell(3)' may be a magic cookie rather than a byte offset; it can be passed to `fseek(3)',
   but not operated on in any meaningful way. The phrase `it hands you a magic cookie' means
   it returns a result whose contents are not defined but which can be passed back to the same
   or some other program later. 2. An in-band code for changing graphic rendition (e.g.,
   inverse video or underlining) or performing other control functions. Some older terminals
   would leave a blank on the screen corresponding to mode-change magic cookies; this was also
   called a {glitch}.  See also {cookie}.

magic number: [UNIX/C] n. 1. In source code, some non-obvious constant whose value is
   significant to the operation of a program and that is inserted inconspicuously in-line
   ({hardcoded}), rather than expanded in by a symbol set by a commented `#define'. Magic
   numbers in this sense are bad style. 2. A number that encodes critical information used in
   an algorithm in some opaque way. The classic examples of these are the numbers used in hash
   or CRC functions, or the coefficients in a linear congruential generator for pseudo-random
   numbers. This sense actually predates and was ancestral to the more common sense 1.
   3. Special data located at the beginning of a binary data file to indicate its type to a
   utility.  Under UNIX, the system and various applications programs (especially the linker)
   distinguish between types of executable file by looking for a magic number. Once upon a
   time, these magic numbers were PDP-11 branch instructions that skipped over header data to
   the start of executable code; the 0407, for example, was octal for `branch 16 bytes
   relative'. Nowadays only a {wizard} knows the spells to create magic numbers. How do you
   choose a fresh magic number of your own? Simple --- you pick one at random. See? It's magic!

magic smoke: n. A substance trapped inside IC packages that enables them to function (also
   called `blue smoke'; this is similar to the archaic `phlogiston' hypothesis about
   combustion). Its existence is demonstrated by what happens when a chip burns up --- the
   magic smoke gets let out, so it doesn't work any more. See {smoke test}, {let the smoke out}.
   USENETter Jay Maynard tells the following story: "Once, while hacking on a dedicated Z80
   system, I was testing code by blowing EPROMs and plugging them in the system, then seeing
   what happened. One time, I plugged one in backwards. I only discovered that *after* I
   realized that Intel didn't put power-on lights under the quartz windows on the tops of
   their EPROMs --- the die was glowing white-hot. Amazingly, the EPROM worked fine after I
   erased it, filled it full of zeros, then erased it again. For all I know, it's still in
   service. Of course, this is because the magic smoke didn't get let out." Compare the
   original phrasing of {Murphy's Law}.

mailing list: n. (often shortened in context to `list') 1. An {email} address that is an alias
   (or {macro}, though that word is never used in this connection) for many other email
   addresses. Some mailing lists are simple `reflectors', redirecting mail sent to them to the
   list of recipients.  Others are filtered by humans or programs of varying degrees of
   sophistication; lists filtered by humans are said to be `moderated'.  2. The people who
   receive your email when you send it to such an address.
   Mailing lists are one of the primary forms of hacker interaction, along with {USENET}. They
   predate USENET, having originated with the first UUCP and ARPANET connections. They are
   often used for private information-sharing on topics that would be too specialized for or
   inappropriate to public USENET groups. Though some of these maintain purely technical
   content (such as the Internet Engineering Task Force mailing list), others (like the
   `sf-lovers' list maintained for many years by Saul Jaffe) are recreational, and others are
   purely social.  Perhaps the most infamous of the social lists was the eccentric bandykin
   distribution; its latter-day progeny, lectroids and tanstaafl, still include a number of
   the oddest and most interesting people in hackerdom.
   Mailing lists are easy to create and (unlike USENET) don't tie up a significant amount of
   machine resources.  Thus, they are often created temporarily by working groups, the members
   of which can then collaborate on a project without ever needing to meet face-to-face. Much
   of the material in this book was criticized and polished on just such a mailing list (called
   `jargon-friends'), which included all the co-authors of Steele-1983.

main loop: n. Software tools are often written to perform some actions repeatedly on whatever
   input is handed to them, terminating when there is no more input or they are explicitly
   told to go away. In such programs, the loop that gets and processes input is called the
   `main loop'.  See also {driver}.

mainframe: n. This term originally referred to the cabinet containing the central processor
   unit or `main frame' of a room-filling {Stone Age} batch machine.  After the emergence of
   smaller `minicomputer' designs in the early 1970s, the traditional {big iron} machines were
   described as `mainframe computers' and eventually just as mainframes. The term carries the
   connotation of a machine designed for batch rather than interactive use, though possibly
   with an interactive timesharing operating system retrofitted onto it; it is especially used
   of machines built by IBM, Unisys, and the other great {dinosaur}s surviving from computing's
   {Stone Age}.
   It is common wisdom among hackers that the mainframe architectural tradition is essentially
   dead (outside of the tiny market for {number-crunching} supercomputers (see {cray})), having
   been swamped by the recent huge advances in IC technology and low-cost personal computing.
   As of 1991, corporate America hasn't quite figured this out yet, though the wave of
   failures, takeovers, and mergers among traditional mainframe makers are certainly straws in
   the wind (see {dinosaurs mating}).

management: n. 1. Corporate power elites distinguished primarily by their distance from actual
   productive work and their chronic failure to manage (see also {suit}).  Spoken derisively,
   as in "*Management* decided that ...".  2. Mythically, a vast bureaucracy responsible for
   all the world's minor irritations. Hackers' satirical public notices are often signed `The
   Mgt'; this derives from the `Illuminatus' novels (see the Bibliography).

mandelbug: /mon'del-buhg/ [from the Mandelbrot set] n. A bug whose underlying causes are so
   complex and obscure as to make its behavior appear chaotic or even non-deterministic. This
   term implies that the speaker thinks it is a {Bohr bug}, rather than a {heisenbug}.

manged: /monjd/ [probably from the French `manger' or Italian `mangiare', to eat; perhaps
   influenced by English n. `mange', `mangy'] adj. Refers to anything that is mangled or
   damaged, usually beyond repair.  "The disk was manged after the electrical storm."  Compare

mangle: vt. Used similarly to {mung} or {scribble}, but more violent in its connotations;
   something that is mangled has been irreversibly and totally trashed.

mangler: [DEC] n. A manager. Compare {mango}; see also {management}. Note that {system mangler}
   is somewhat different in connotation.

mango: /mang'go/ [orig. in-house jargon at Symbolics] n. A manager. Compare {mangler}. See
   also {devo} and {doco}.

marbles: [from mainstream "lost all his/her marbles"] pl.n. The minimum needed to build your
   way further up some hierarchy of tools or abstractions.  After a bad system crash, you need
   to determine if the machine has enough marbles to come up on its own, or enough marbles to
   allow a rebuild from backups, or if you need to rebuild from scratch. "This compiler doesn't
   even have enough marbles to compile `Hello World'."

marginal: adj. 1. Extremely small.  "A marginal increase in {core} can decrease {GC} time
   drastically."  In everyday terms, this means that it is a lot easier to clean off your desk
   if you have a spare place to put some of the junk while you sort through it. 2. Of extremely
   small merit. "This proposed new feature seems rather marginal to me." 3. Of extremely small
   probability of {win}ning. "The power supply was rather marginal anyway; no wonder it fried."

Marginal Hacks: n. Margaret Jacks Hall, a building into which the Stanford AI Lab was moved
   near the beginning of the 1980s (from the {D. C. Power Lab}).

marginally: adv. Slightly. "The ravs here are only marginally better than at Small Eating
   Place."  See {epsilon}.

marketroid: /mar'k*-troyd/ alt. `marketing slime', `marketing droid', `marketeer' n. A member
   of a company's marketing department, esp. one who promises users that the next version of a
   product will have features that are not actually scheduled for inclusion, are extremely
   difficult to implement, and/or are in violation of the laws of physics; and/or one who
   describes existing features (and misfeatures) in ebullient, buzzword-laden adspeak.
   Derogatory.  Compare {droid}.

Mars: n. A legendary tragic failure, the archetypal Hacker Dream Gone Wrong. Mars was the code
   name for a family of PDP-10 compatible computers built by Systems Concepts (now, The SC
   Group); the multi-processor SC-30M, the small uniprocessor SC-25M, and the never-built
   superprocessor SC-40M. These machines were marvels of engineering design; although not much
   slower than the unique {Foonly} F-1, they were physically smaller and consumed less power
   than the much slower DEC KS10 or Foonly F-2, F-3, or F-4 machines. They were slso completely
   compatible with the DEC KL10, and ran all KL10 binaries, including the operating system,
   with no modifications at about 2--3 times faster than a KL10.
   When DEC cancelled the Jupiter project in 1983, Systems Concepts should have made a bundle
   selling their machine into shops with a lot of software investment in PDP-10s, and in fact
   their spring 1984 announcement generated a great deal of excitement in the PDP-10 world.
   TOPS-10 was running on the Mars by the summer of 1984, and TOPS-20 by early fall.
   Unfortunately, the hackers running Systems Concepts were much better at designing machines
   than in mass producing or selling them; the company allowed itself to be sidetracked by a
   bout of perfectionism into continually improving the design, and lost credibility as
   delivery dates continued to slip. They also overpriced the product ridiculously; they
   believed they were competing with the KL10 and VAX 8600 and failed to reckon with the likes
   of Sun Microsystems and other hungry startups building workstations with power comparable
   to the KL10 at a fraction of the price. By the time SC shipped the first SC-30M to Stanford
   in late 1985, most customers had already made the traumatic decision to abandon the PDP-10,
   usually for VMS or UNIX boxes. Most of the Mars computers built ended up being purchased by
   This tale and the related saga of Foonly hold a lesson for hackers: if you want to play in
   the Real World, you need to learn Real World moves.

martian: n. A packet sent on a TCP/IP network with a source address of the test loopback
   interface []. This means that it will come back at you labeled with a source
   address that is clearly not of this earth. "The domain server is getting lots of packets
   from Mars.  Does that gateway have a martian filter?"

massage: vt. Vague term used to describe `smooth' transformations of a data set into a
   different form, esp. transformations that do not lose information.  Connotes less pain than
   {munch} or {crunch}. "He wrote a program that massages X bitmap files into GIF format."
   Compare {slurp}.

math-out: [poss. from `white-out' (the blizzard variety)] n. A paper or presentation so
   encrusted with mathematical or other formal notation as to be incomprehensible. This may be
   a device for concealing the fact that it is actually {content-free}. See also {numbers},
   {social science number}.

Matrix: [FidoNet] n. 1. What the Opus BBS software and sysops call {FidoNet}. 2. Fanciful term
   for a {cyberspace} expected to emerge from current networking experiments (see {network,
   the}). Some people refer to the totality of present networks this way.

Mbogo, Dr. Fred: /*m-boh'goh, dok'tr fred/ [Stanford] n. The archetypal man you don't want to
   see about a problem, esp. an incompetent professional; a shyster. "Do you know a good eye
   doctor?"  "Sure, try Mbogo Eye Care and Professional Dry Cleaning." The name comes from
   synergy between {bogus} and the original Dr. Mbogo, a witch doctor who was Gomez Addams'
   physician on the old "Addams Family" TV show.  See also {fred}.

meatware: n. Synonym for {wetware}.  Less common.

meeces: /mees'*z/ [TMRC] n. Occasional furry visitors who are not {urchin}s. [That is, mice.
   This may no longer be in live use; it clearly derives from the refrain of the early-1960s
   cartoon character Mr. Jinx: "I hate meeces to *pieces*!" --- ESR]

meg: /meg/ n. See {{quantifiers}}.

mega-: /me'g*/ [SI] pref. See {{quantifiers}}.

megapenny: /meg'*-pen`ee/ n. $10,000 (1 cent * 10^6). Used semi-humourously as a unit in
   comparing computer cost and performance figures.

MEGO: /me'goh/ or /mee'goh/ [`My Eyes Glaze Over', often `Mine Eyes Glazeth (sic) Over',
   attributed to the futurologist Herman Kahn] Also `MEGO factor'. 1. n. A {handwave} intended
   to confuse the listener and hopefully induce agreement because the listener does not want to
   admit to not understanding what is going on. MEGO is usually directed at senior management
   by engineers and contains a high proportion of {TLA}s. 2. excl. An appropriate response to
   MEGO tactics.  3. Among non-hackers this term often refers not to behavior that causes the
   eyes to glaze, but to the eye-glazing reaction itself, which may be triggered by the mere
   threat of technical detail as effectively as by an actual excess of it.

meltdown, network: n.  See {network meltdown}.

meme: /meem/ [coined on analogy with `gene' by Richard Dawkins] n. An idea considered as a
   {replicator}, esp. with the connotation that memes parasitize people into propagating them
   much as viruses do.  Used esp. in the phrase `meme complex' denoting a group of mutually
   supporting memes that form an organized belief system, such as a religion.  This lexicon is
   an (epidemiological) vector of the `hacker subculture' meme complex; each entry might be
   considered a meme.  However, `meme' is often misused to mean `meme complex'. Use of the
   term connotes acceptance of the idea that in humans (and presumably other tool- and
   language-using sophonts) cultural evolution by selection of adaptive ideas has superseded
   biological evolution by selection of hereditary traits.  Hackers find this idea congenial
   for tolerably obvious reasons.

meme plague: n. The spread of a successful but pernicious {meme}, esp. one that parasitizes
   the victims into giving their all to propagate it.  Astrology, BASIC, and the other guy's
   religion are often considered to be examples.  This usage is given point by the historical
   fact that `joiner' ideologies like Naziism or various forms of millennarian Christianity
   have exhibited plague-like cycles of exponential growth followed by collapses to small
   reservoir populations.

memetics: /me-met'iks/ [from {meme}] The study of memes.  As of mid-1991, this is still an
   extremely informal and speculative endeavor, though the first steps towards at least
   statistical rigor have been made by H. Keith Henson and others. Memetics is a popular topic
   for speculation among hackers, who like to see themselves as the architects of the new
   information ecologies in which memes live and replicate.

memory leak: n. An error in a program's dynamic-store allocation logic that causes it to fail
   to reclaim discarded memory, leading to eventual collapse due to memory exhaustion.  Also
   (esp. at CMU) called {core leak}. See {aliasing bug}, {fandango on core}, {smash the stack},
   {precedence lossage}, {overrun screw}, {leaky heap}, {leak}.

menuitis: /men`yoo-i:'tis/ n. Notional disease suffered by software with an obsessively
   simple-minded menu interface and no escape. Hackers find this intensely irritating and much
   prefer the flexibility of command-line or language-style interfaces, especially those
   customizable via macros or a special-purpose language in which one can encode useful hacks.
   See {user-obsequious}, {drool-proof paper}, {WIMP environment}, {for the rest of us}.

mess-dos: /mes-dos/ n. Derisory term for MS-DOS. Often followed by the ritual banishing "Just
   say No!" See {{MS-DOS}}. Most hackers (even many MS-DOS hackers) loathe MS-DOS for its
   single-tasking nature, its limits on application size, its nasty primitive interface, and
   its ties to IBMness (see {fear and loathing}).  Also `mess-loss', `messy-dos', `mess-dog',
   `mess-dross', `mush-dos', and various combinations thereof.  In Ireland and the U.K. it is
   even sometimes called `Domestos' after a brand of toilet cleanser.

meta: /me't*/ or /may't*/ or (Commonwealth) /mee't*/ [from analytic philosophy] adj.,pref. One
   level of description up. A meta-syntactic variable is a variable in notation used to
   describe syntax, and meta-language is language used to describe language. This is difficult
   to explain briefly, but much hacker humor turns on deliberate confusion between meta-levels.
   See {{Humour, Hacker}}.

meta bit: n. The top bit of an 8-bit character, which is on in character values 128--255. Also
   called {high bit}, {alt bit}, or {hobbit}.  Some terminals and consoles (see {space-cadet
   keyboard}) have a META shift key.  Others (including, *mirabile dictu*, keyboards on IBM
   PC-class machines) have an ALT key.  See also {bucky bits}.

MFTL: /M-F-T-L/ [acronym: `My Favorite Toy Language'] 1. adj. Describes a talk on a programming
   language design that is heavy on the syntax (with lots of BNF), sometimes even talks about
   semantics (e.g., type systems), but rarely, if ever, has any content (see {content-free}).
   More broadly applied to talks --- even when the topic is not a programming language --- in
   which the subject matter is gone into in unnecessary and meticulous detail at the sacrifice
   of any conceptual content.  "Well, it was a typical MFTL talk".  2. n. Describes a language
   about which the developers are passionate (often to the point of prosyletic zeal) but no one
   else cares about.  Applied to the language by those outside the originating group. "He
   cornered me about type resolution in his MFTL."
   The first great goal in the mind of the designer of an MFTL is usually to write a compiler
   for it, then bootstrap the design away from contamination by lesser languages by writing a
   compiler for it in itself.  Thus, the standard put-down question at an MFTL talk is "Has it
   been used for anything besides its own compiler?". On the other hand, a language that
   *cannot* be used to write its own compiler is beneath contempt...

mickey: n. The resolution unit of mouse movement. It has been suggested that the `disney' will
   become a benchmark unit for animation graphics performance.

mickey mouse program: n. North American equivalent of a {noddy} (that is, trivial) program.
   Doesn't necessarily have the belittling connotations of mainstream slang "Oh, that's just
   mickey mouse stuff!"; sometimes trivial programs can be very useful.

micro-: pref. 1. Very small; this is the root of its use as a quantifier prefix. 2. A
   quantifier prefix, calling for multiplication by 10^{-6} (see {{quantifiers}}). Neither of
   these uses is peculiar to hackers, but hackers tend to fling them both around rather more
   freely than is countenanced in standard English. It is recorded, for example, that one CS
   professor used to characterize the standard length of his lectures as a microcentury ---
   that is, about 52.6 minutes (see also {attoparsec}, {nanoacre}, and especially
   {microfortnight}).  3. Personal or human-scale --- that is, capable of being maintained or
   comprehended or manipulated by one human being. This sense is generalized from
   `microcomputer', and is esp. used in contrast with `macro-' (the corresponding Greek prefix
   meaning `large'). 4. Local as opposed to global (or {macro-}). Thus a hacker might say that
   buying a smaller car to reduce pollution only solves a microproblem; the macroproblem of
   getting to work might be better solved by using mass transit, moving to within walking
   distance, or (best of all) telecommuting.

microfloppies: n. 3.5-inch floppies, as opposed to 5.25-inch {vanilla} or mini-floppies and
   the now-obsolete 8-inch variety. This term may be headed for obsolescence as 5.25-inchers
   pass out of use, only to be revived if anybody floats a sub-3-inch floppy standard. See
   {stiffy}, {minifloppies}.

microfortnight: n. About 1.2 sec. The VMS operating system has a lot of tuning parameters that
   you can set with the SYSGEN utility, and one of these is TIMEPROMPTWAIT, the time the
   system will wait for an operator to set the correct date and time at boot if it realizes
   that the current value is bogus.  This time is specified in microfortnights!
   Multiple uses of the millifortnight (about 20 minutes) and {nanofortnight} have also been

microLenat: /mi:-kroh-len'-*t/ n. See {bogosity}.

microReid: /mi:'kroh-reed/ n. See {bogosity}.

Microsloth Windows: /mi:'kroh-sloth` win'dohz/ n. Hackerism for `Microsoft Windows', a
   windowing system for the IBM-PC which is so limited by bug-for-bug compatibility with
   {mess-dos} that it is agonizingly slow on anything less than a fast 386.  Compare {X},

microtape: /mi:'kroh-tayp/ n. Occasionally used to mean a DECtape, as opposed to a {macrotape}.
   A DECtape is a small reel, about 4 inches in diameter, of magnetic tape about an inch wide.
   Unlike drivers for today's {macrotape}s, microtape drivers allow random access to the data,
   and therefore could be used to support file systems and even for swapping (this was
   generally done purely for {hack value}, as they were far too slow for practical use). In
   their heyday they were used in pretty much the same ways one would now use a floppy disk:
   as a small, portable way to save and transport files and programs. Apparently the term
   `microtape' was actually the official term used within DEC for these tapes until someone
   coined the word `DECtape', which, of course, sounded sexier to the {marketroid}s.

middle-endian: adj. Not {big-endian} or {little-endian}. Used of perverse byte orders such as
   3-4-1-2 or 2-1-4-3, occasionally found in the packed-decimal formats of minicomputer
   manufacturers who shall remain nameless.  See {NUXI problem}.

milliLampson: /mil'*-lamp`sn/ n. A unit of talking speed, abbreviated mL. Most people run
   about 200 milliLampsons. Butler Lampson (a CS theorist and systems implementor highly
   regarded among hackers) goes at 1000. A few people speak faster. This unit is sometimes
   used to compare the (sometimes widely disparate) rates at which people can generate ideas
   and actually emit them in speech.  For example, noted computer architect C. Gordon Bell
   (designer of the PDP-11) is said, with some awe, to think at about 1200 mL but only talk at
   about 300; he is frequently reduced to fragments of sentences as his mouth tries to keep up
   with his speeding brain.

minifloppies: n. 5.25-inch {vanilla} floppy disks, as opposed to 3.5-inch or {microfloppies}
   and the now-obsolescent 8-inch variety.  At one time, this term was a trademark of Shugart
   Associates for their SA-400 minifloppy drive.  Nobody paid any attention.  See {stiffy}.

MIPS: /mips/ [acronym] n. 1. A measure of computing speed; formally, `Million Instructions Per
   Second' (that's 10^6 per second, not 2^{20}!); often rendered by hackers as `Meaningless
   Indication of Processor Speed' or in other unflattering ways.  This joke expresses a nearly
   universal attitude about the value of most {benchmark} claims, said attitude being one of
   the great cultural divides between hackers and {marketroid}s.  The singular is sometimes `1
   MIP' even though this is clearly etymologically wrong. See also {KIPS} and {GIPS}. 2.
   Computers, especially large computers, considered abstractly as sources of {computron}s.
   "This is just a workstation; the heavy MIPS are hidden in the basement." 3. The corporate
   name of a particular RISC-chip company; among other things, they designed the processor
   chips used in DEC's 3100 workstation series.  4. Acronym for `Meaningless Information per
   Second' (a joke, prob. from sense 1).

misbug: /mis-buhg/ [MIT] n. An unintended property of a program that turns out to be useful;
   something that should have been a {bug} but turns out to be a {feature}.  Usage: rare.
   Compare {green lightning}. See {miswart}.

misfeature: /mis-fee'chr/ or /mis'fee`chr/ n. A feature that eventually causes lossage,
   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 substantial philosophical change to the
   structure of the system involved. A misfeature is different from a simple unforeseen side
   effect; the term implies that the misfeature was actually carefully planned to be that way,
   but its future consequences or circumstances just weren't predicted accurately. This is
   different from just not having thought ahead about it at all.  Many misfeatures (especially
   in user-interface design) arise because the designers/implementors mistook their personal
   tastes for laws of nature. 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 is kind of a misfeature that file names are limited to 6
   characters, but the original implementors wanted to save directory space and we're stuck
   with it for now."

Missed'em-five: n. Pejorative hackerism for AT&T System V UNIX, generally used by {BSD}
   partisans in a bigoted mood. (The synonym `SysVile' is also encountered.) See {software
   bloat}, {Berzerkeley}.

miswart: /mis-wort/ [from {wart} by analogy with {misbug}] n. A {feature} that superficially
   appears to be a {wart} but has been determined to be the {Right Thing}. For example, in
   some versions of the {EMACS} text editor, the `transpose characters' command exchanges the
   two characters on either side of the cursor on the screen, *except* when the cursor is at
   the end of a line, in which case the two characters before the cursor are exchanged. While
   this behavior is perhaps surprising, and certainly inconsistent, it has been found through
   extensive experimentation to be what most users want.  This feature is a miswart.

moby: /moh'bee/ [MIT: seems to have been in use among model railroad fans years ago. Derived
   from Melville's `Moby Dick' (some say from `Moby Pickle').] 1. adj. Large, immense, complex,
   impressive.  "A Saturn V rocket is a truly moby frob." "Some MIT undergrads pulled off a
   moby hack at the Harvard-Yale game." (See appendix A). 2. n. obs. The maximum address space
   of a machine (see below).  For a 680[234]0 or VAX or most modern 32-bit architectures, it
   is 4,294,967,296 8-bit bytes (4 gigabytes).  3. A title of address (never of third-person
   reference), usually used to show admiration, respect, and/or friendliness to a competent
   hacker.  "Greetings, moby Dave.  How's that address-book thing for the Mac going?"  4. adj.
   In backgammon, doubles on the dice, as in `moby sixes', `moby ones', etc.  Compare this
   with {bignum} (sense 2): double sixes are both bignums and moby sixes, but moby ones are
   not bignums (the use of `moby' to describe double ones is sarcastic).  Standard emphatic
   forms: `Moby foo', `moby win', `moby loss'.  `Foby moo': a spoonerism due to Richard
   This term entered hackerdom with the Fabritek 256K memory added to the MIT AI PDP-6
   machine, which was considered unimaginably huge when it was installed in the 1960s (at a
   time when a more typical memory size for a timesharing system was 72 kilobytes). Thus, a
   moby is classically 256K 36-bit words, the size of a PDP-6 or PDP-10 moby.  Back when
   address registers were narrow the term was more generally useful, because when a computer
   had virtual memory mapping, it might actually have more physical memory attached to it than
   any one program could access directly.  One could then say "This computer has 6 mobies"
   meaning that the ratio of physical memory to address space is 6, without having to say
   specifically how much memory there actually is.  That in turn implied that the computer
   could timeshare six `full-sized' programs without having to swap programs between memory
   and disk.
   Nowadays the low cost of processor logic means that address spaces are usually larger than
   the most physical memory you can cram onto a machine, so most systems have much *less* than
   one theoretical `native' moby of core.  Also, more modern memory-management techniques
   (esp. paging) make the `moby count' less significant. However, there is one series of
   popular chips for which the term could stand to be revived --- the Intel 8088 and 80286
   with their incredibly {brain-damaged} segmented-memory designs.  On these, a `moby' would
   be the 1-megabyte address span of a segment/offset pair (by coincidence, a PDP-10 moby was
   exactly 1 megabyte of 9-bit bytes).

mod: vt.,n. 1. Short for `modify' or `modification'.  Very commonly used --- in fact the full
   terms are considered markers that one is being formal. The plural `mods' is used esp. with
   reference to bug fixes or minor design changes in hardware or software, most esp. with
   respect to {patch} sets or a {diff}. 2. Short for {modulo} but used *only* for its
   techspeak sense.

mode: n. A general state, usually used with an adjective describing the state. Use of the word
   `mode' rather than `state' implies that the state is extended over time, and probably also
   that some activity characteristic of that state is being carried out. "No time to hack; I'm
   in thesis mode."  In its jargon sense, `mode' is most often attributed to people, though it
   is sometimes applied to programs and inanimate objects. In particular, see {hack mode},
   {day mode}, {night mode}, {demo mode}, {fireworks mode}, and {yoyo mode}; also {talk mode}.
   One also often hears the verbs `enable' and `disable' used in connection with jargon modes.
   Thus, for example, a sillier way of saying "I'm going to crash" is "I'm going to enable
   crash mode now".  One might also hear a request to "disable flame mode, please".

mode bit: n. A {flag}, usually in hardware, that selects between two (usually quite different)
   modes of operation. The connotations are different from {flag} bit in that mode bits are
   mainly written during a boot or set-up phase, are seldom explicitly read, and seldom change
   over the lifetime of an ordinary program. The classic example was the EBCDIC-vs.-ASCII bit
   (#12) of the Program Status Word of the IBM 360.  Another was the bit on a PDP-12 that
   controlled whether it ran the PDP-8 or the LINC instruction set.

modulo: /mo'dyu-loh/ prep. Except for. From mathematical terminology; one can consider saying
   that 4 = 22 except for the 9s (4 = 22 mod 9). "Well, LISP seems to work okay now, modulo
   that {GC} bug." "I feel fine today modulo a slight headache."

molly-guard: /mol'ee-gard/ [University of Illinois] n. A shield to prevent tripping of some
   {Big Red Switch} by clumsy or ignorant hands.  Originally used of some plexiglass covers
   improvised for the BRS on an IBM 4341 after a programmer's toddler daughter (named Molly)
   frobbed it twice in one day. Later generalized to covers over stop/reset switches on disk
   drives and networking equipment.

Mongolian Hordes technique: n. Development by {gang bang} (poss. from the Sixties
   counterculture expression `Mongolian clusterf**k' for a public orgy). Implies that large
   numbers of inexperienced programmers are being put on a job better performed by a few
   skilled ones.  Also called `Chinese Army technique'; see also {Brooks's Law}.

monkey up: vt. To hack together hardware for a particular task, especially a one-shot job.
   Connotes an extremely {crufty} and consciously temporary solution.  Compare {hack up},
   {kluge up}, {cruft together}, {cruft together}.

monkey, scratch: n.  See {scratch monkey}.

monstrosity: 1. n. A ridiculously {elephantine} program or system, esp. one that is buggy or
   only marginally functional. 2. The quality of being monstrous (see `Overgeneralization' in
   the discussion of jargonification).  See also {baroque}.

Moof: /moof/ [MAC users] n. The Moof or `dogcow' is a semi-legendary creature that lurks in
   the depths of the Macintosh Technical Notes Hypercard stack V3.1; specifically, the full
   story of the dogcow is told in technical note #31 (the particular Moof illustrated is
   properly named `Clarus'). Option-shift-click will cause it to emit a characteristic `Moof!'
   or `!fooM' sound. *Getting* to tech note 31 is the hard part; to discover how to do that,
   one must needs examine the stack script with a hackerly eye.  Clue: {rot13} is involved.
   A dogcow also appears if you choose `Page Setup...' with a LaserWriter selected and click
   on the `Options' button.

Moore's Law: /morz law/ prov. The observation that the logic density of silicon integrated
   circuits has closely followed the curve (bits per square inch)  = 2^{(n - 1962)}; that is,
   the amount of information storable in one square inch of silicon has roughly doubled yearly
   every year since the technology was invented.  See also {Parkinson's Law of Data}.

moria: /mor'ee-*/ n. Like {nethack} and {rogue}, one of the large PD Dungeons-and-Dragons-like
   simulation games, available for a wide range of machines and operating systems.  Extremely
   addictive and a major consumer of time better used for hacking.

MOTAS: /moh-toz/ [USENET: Member Of The Appropriate Sex, after {MOTOS} and {MOTSS}] n. A
   potential or (less often) actual sex partner.  See also {SO}.

MOTOS: /moh-tohs/ [acronym from the 1970 U.S. census forms via USENET: Member Of The Opposite
   Sex] n. A potential or (less often) actual sex partner.  See {MOTAS}, {MOTSS}, {SO}.  Less
   common than MOTSS or {MOTAS}, which have largely displaced it.

MOTSS: /mots/ or /M-O-T-S-S/ [from the 1970 U.S. census forms via USENET, Member Of The Same
   Sex] n. Esp. one considered as a possible sexual partner. The gay-issues newsgroup on USENET
   is called soc.motss.  See {MOTOS} and {MOTAS}, which derive from it.  Also see {SO}.

mouse ahead: vi. Point-and-click analog of `type ahead'. To manipulate a computer's pointing
   device (almost always a mouse in this usage, but not necessarily) and its selection or
   command buttons before a computer program is ready to accept such input, in anticipation of
   the program accepting the input.  Handling this properly is rare, but it can help make a
   {WIMP environment} much more usable, assuming the users are familiar with the behavior of
   the user interface.

mouse around: vi. To explore public portions of a large system, esp. a network such as
   Internet via {FTP} or {TELNET}, looking for interesting stuff to {snarf}.

mouse belt: n. See {rat belt}.

mouse droppings: [MS-DOS] n. Pixels (usually single) that are not properly restored when the
   mouse pointer moves away from a particular location on the screen, producing the appearance
   that the mouse pointer has left droppings behind. The major causes for this problem are
   programs that write to the screen memory corresponding to the mouse pointer's current
   location without hiding the mouse pointer first, and mouse drivers that do not quite support
   the graphics mode in use.

mouse elbow: n. A tennis-elbow-like fatigue syndrome resulting from excessive use of a {WIMP
   environment}.  Similarly, `mouse shoulder'; GLS reports that he used to get this a lot
   before he taught himself to be ambimoustrous.

mouso: /mow'soh/ n. [by analogy with `typo'] An error in mouse usage resulting in an
   inappropriate selection or graphic garbage on the screen.  Compare {thinko}, {braino}.

MS-DOS:: /M-S-dos/ [MicroSoft Disk Operating System] n. A {clone} of {{CP/M}} for the 8088
   crufted together in 6 weeks by hacker Tim Paterson, who is said to have regretted it ever
   since. Numerous features, including vaguely UNIX-like but rather broken support for
   subdirectories, I/O redirection, and pipelines, were hacked into 2.0 and subsequent
   versions; as a result, there are two or more incompatible versions of many system calls,
   and MS-DOS programmers can never agree on basic things like what character to use as an
   option switch or whether to be case-sensitive. The resulting mess is now the highest-unit-
   volume OS in history. Often known simply as DOS, which annoys people familiar with other
   similarly abbreviated operating systems (the name goes back to the mid-1960s, when it was
   attached to IBM's first disk operating system for the 360).  Some people like to pronounce
   DOS like "dose", as in "I don't work on dose, man!", or to compare it to a dose of
   brain-damaging drugs (a slogan button in wide circulation among hackers exhorts: "MS-DOS:
   Just say No!").  See {mess-dos}, {ill-behaved}.

mu: /moo/ The correct answer to the classic trick question "Have you stopped beating your wife
   yet?". Assuming that you have no wife or you have never beaten your wife, the answer "yes"
   is wrong because it implies that you used to beat your wife and then stopped, but "no" is
   worse because it suggests that you have one and are still beating her. According to various
   Discordians and Douglas Hofstadter (see the Bibliography), the correct answer is usually
   "mu", a Japanese word alleged to mean "Your question cannot be answered because it depends
   on incorrect assumptions". Hackers tend to be sensitive to logical inadequacies in language,
   and many have adopted this suggestion with enthusiasm.  The word `mu' is actually from
   Chinese, meaning `nothing'; it is used in mainstream Japanese in that sense, but native
   speakers do not recognize the Discordian question-denying use. It almost certainly derives
   from overgeneralization of the answer in the following well-known Rinzei Zen teaching

     A monk asked Joshu, "Does a dog have the Buddha nature?"  Joshu retorted, "Mu!"

   See also {has the X nature}, {AI Koans}, and Douglas Hofstadter's `G"odel, Escher, Bach'
   (pointer in the Bibliography).

MUD: /muhd/ [acronym, Multi-User Dungeon; alt. Multi-User Dimension] 1. n. A class of {virtual
   reality} experiments accessible via the Internet.  These are real-time chat forums with
   structure; they have multiple `locations' like an adventure game, and may include combat,
   traps, puzzles, magic, a simple economic system, and the capability for characters to build
   more structure onto the database that represents the existing world.  2. vi. To play a MUD
   (see {hack-and-slay}).  The acronym MUD is often lowercased and/or verbed; thus, one may
   speak of `going mudding', etc.
   Historically, MUDs (and their more recent progeny with names of MU-form) derive from an AI
   experiment by Richard Bartle and Roy Trubshaw on the University of Essex's DEC-10 in the
   early 1980s; descendants of that game still exist today (see {BartleMUD}). The title `MUD'
   is still trademarked to the commercial MUD run by Bartle on British Telecom (the motto:
   "You haven't *lived* 'til you've *died* on MUD!"); however, this did not stop students on
   the European academic networks from copying and improving on the MUD concept, from which
   sprung several new MUDs (VAXMUD, AberMUD, LPMUD).  Many of these had associated bulletin-
   board systems for social interaction.  Because USENET feeds have been spotty and difficult
   to get in the U.K.  and the British JANET network doesn't support {FTP} or remote login via
   telnet, the MUDs became major foci of hackish social interaction there.
   AberMUD and other variants crossed the Atlantic around 1988 and quickly gained popularity
   in the U.S.; they became nuclei for large hacker communities with only loose ties to
   traditional hackerdom (some observers see parallels with the growth of USENET in the early
   1980s).  The second wave of MUDs (TinyMUD and variants) tended to emphasize social
   interaction, puzzles, and cooperative world-building as opposed to combat and competition.
   In 1991, over 50% of MUD sites are of a third major variety, LPMUD, which synthesizes the
   combat/puzzle aspects of AberMUD and older systems with the extensibility of TinyMud. The
   trend toward greater programmability and flexibility will doubtless continue.
   The state of the art in MUD design is still moving very rapidly, with new simulation designs
   appearing (seemingly) every month. There is now (early 1991) a move afoot to deprecate the
   term {MUD} itself, as newer designs exhibit an exploding variety of names corresponding to
   the different simulation styles being explored.  See also {BartleMUD}, {berserking},
   {bonk/oif}, {brand brand brand}, {FOD}, {hack-and-slay}, {link-dead}, {mudhead}, {posing},
   {talk mode}, {tinycrud}.

mudhead: n. Commonly used to refer to a {MUD} player who sleeps, breathes, and eats MUD.
   Mudheads have been known to fail their degrees, drop out, etc., with the consolation,
   however, that they made wizard level.  When encountered in person, all a mudhead will talk
   about is two topics: the tactic, character, or wizard that is supposedly always unfairly
   stopping him/her from becoming a wizard or beating a favourite MUD, and the MUD he or she is
   writing or going to write because all existing MUDs are so dreadful!  See also {wannabee}.

multician: /muhl-ti'shn/ [coined at Honeywell, ca. 1970] n. Competent user of {{Multics}}.
   Perhaps oddly, no one has ever promoted the analogous `Unician'.

Multics:: /muhl'tiks/ n. [from "MULTiplexed Information and Computing Service"] An early (late
   1960s) timesharing operating system co-designed by a consortium including MIT, GE, and Bell
   Laboratories.  Very innovative for its time --- among other things, it introduced the idea
   of treating all devices uniformly as special files.  All the members but GE eventually
   pulled out after determining that {second-system effect} had bloated Multics to the point
   of practical unusability (the `lean' predecessor in question was {CTSS}).  Honeywell
   commercialized Multics after buying out GE's computer group, but it was never very
   successful (among other things, on some versions one was commonly required to enter a
   password to log out).  One of the developers left in the lurch by the project's breakup was
   Ken Thompson, a circumstance which led directly to the birth of {{UNIX}}.  For this and
   other reasons, aspects of the Multics design remain a topic of occasional debate among
   hackers.  See also {brain-damaged} and {GCOS}.

multitask: n. Often used of humans in the same meaning it has for computers, to describe a
   person doing several things at once (but see {thrash}).  The term `multiplex', from
   communications technology (meaning to handle more than one channel at the same time), is
   used similarly.

mumblage: /muhm'bl*j/ n. The topic of one's mumbling (see {mumble}). "All that mumblage" is
   used like "all that stuff" when it is not quite clear how the subject of discussion works,
   or like "all that crap" when `mumble' is being used as an implicit replacement for

mumble: interj. 1. Said when the correct response is 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 long discussion.  "Don't you think that we could improve LISP
   performance by using a hybrid reference-count transaction garbage collector, if the cache
   is big enough and there are some extra cache bits for the microcode to use?"  "Well,
   mumble ... I'll have to think about it." 2. Sometimes used as an expression of disagreement.
   "I think we should buy a {VAX}."  "Mumble!"  Common variant: `mumble frotz' (see {frotz};
   interestingly, one does not say `mumble frobnitz' even though `frotz' is short for
   `frobnitz').  3. Yet another metasyntactic variable, like {foo}. 4. When used as a question
   ("Mumble?") means "I didn't understand you". 5. Sometimes used in `public' contexts on-line
   as a placefiller for things one is barred from giving details about. For example, a poster
   with pre-released hardware in his machine might say "Yup, my machine now has an extra 16M
   of memory, thanks to the card I'm testing for Mumbleco."

munch: [often confused with {mung}, q.v.] vt. To transform information in a serial fashion,
   often requiring large amounts of computation.  To trace down a data structure. Related to
   {crunch} and nearly synonymous with {grovel}, but connotes less pain.

munching: n. Exploration of security holes of someone else's computer for thrills, notoriety,
   or to annoy the system manager.  Compare {cracker}.  See also {hacked off}.

munching squares: n. A {display hack} dating back to the PDP-1 (ca. 1962, reportedly discovered
   by Jackson Wright), which employs a trivial computation (repeatedly plotting the graph Y = X
   XOR T for successive values of T --- see {HAKMEM} items 146--148) to produce an impressive
   display of moving and growing squares that devour the screen.  The initial value of T is
   treated as a parameter, which, when well-chosen, can produce amazing effects. Some of these,
   later (re)discovered on the LISP machine, have been christened `munching triangles' (try AND
   for XOR and toggling points instead of plotting them), `munching w's', and `munching mazes'.
   More generally, suppose a graphics program produces an impressive and ever-changing display
   of some basic form, foo, on a display terminal, and does it using a relatively simple
   program; then the program (or the resulting display) is likely to be referred to as
   `munching foos' (this is a good example of the use of the word {foo} as a metasyntactic

munchkin: /muhnch'kin/ [from the squeaky-voiced little people in L. Frank Baum's `The Wizard
   of Oz'] n. A teenage-or-younger micro enthusiast hacking BASIC or something else equally
   constricted. A term of mild derision --- munchkins are annoying but some grow up to be
   hackers after passing through a {larval stage}. The term {urchin} is also used. See also
   {wannabee}, {bitty box}.

mundane: [from SF fandom] n. 1. A person who is not in science fiction fandom. 2. A person who
   is not in the computer industry. In this sense, most often an adjectival modifier as in "in
   my mundane life...." See also {Real World}.

mung: /muhng/ alt. `munge' /muhnj/ [in 1960 at MIT, `Mash Until No Good'; sometime after that
   the derivation from the {{recursive acronym}} `Mung Until No Good' became standard] vt.
   1. To make changes to a file, esp. large-scale and irrevocable changes. See {BLT}. 2. To
   destroy, usually accidentally, occasionally maliciously. The system only mungs things
   maliciously; this is a consequence of {Finagle's Law}. See {scribble}, {mangle}, {trash},
   {nuke}. Reports from {USENET} suggest that the pronunciation /muhnj/ is now usual in speech,
   but the spelling `mung' is still common in program comments (compare the widespread
   confusion over the proper spelling of {kluge}).  3. The kind of beans of which the sprouts
   are used in Chinese food.  (That's their real name!  Mung beans!  Really!)

Murphy's Law: prov. The correct, *original* Murphy's Law reads: "If there are two or more ways
   to do something, and one of those ways can result in a catastrophe, then someone will do
   it." This is a principle of defensive design, cited here because it is usually given in
   mutant forms less descriptive of the challenges of design for lusers. For example, you don't
   make a two-pin plug symmetrical and then label it `THIS WAY UP'; if it matters which way it
   is plugged in, then you make the design asymmetrical (see also the anecdote under {magic
   Edward A. Murphy, Jr. was one of the engineers on the rocket-sled experiments that were done
   by the U.S. Air Force in 1949 to test human acceleration tolerances. One experiment involved
   a set of 16 accelerometers mounted to different parts of the subject's body. There were two
   ways each sensor could be glued to its mount, and somebody methodically installed all 16 the
   wrong way around. Murphy then made the original form of his pronouncement, which the test
   subject (Major John Paul Stapp) quoted at a news conference a few days later.
   Within months `Murphy's Law' had spread to various technical cultures connected to aerospace
   engineering.  Before too many years had gone by variants had passed into the popular
   imagination, changing as they went.  Most of these are variants on "Anything that can go
   wrong, will"; this is sometimes referred to as {Finagle's Law}.  The memetic drift apparent
   in these mutants clearly demonstrates Murphy's Law acting on itself!

Music:: n. A common extracurricular interest of hackers (compare {{science-fiction fandom}},
   {{oriental food}}; see also {filk}).  Hackish folklore has long claimed that musical and
   programming abilities are closely related, and there has been at least one large-scale
   statistical study that supports this. Hackers, as a rule, like music and often develop
   musical appreciation in unusual and interesting directions. Folk music is very big in hacker
   circles; so is electronic music, and the sort of elaborate instrumental jazz/rock that used
   to be called `progressive' and isn't recorded much any more.  The hacker's musical range
   tends to be wide; many can listen with equal appreciation to (say) Talking Heads, Yes,
   Gentle Giant, Spirogyra, Scott Joplin, Tangerine Dream, King Sunny Ade, The Pretenders, or
   Bach's Brandenburg Concerti.  It is also apparently true that hackerdom includes a much
   higher concentration of talented amateur musicians than one would expect from a
   similar-sized control group of {mundane} types.

mutter: vt. To quietly enter a command not meant for the ears, eyes, or fingers of ordinary
   mortals.  Often used in `mutter an {incantation}'.  See also {wizard}.

JGC Logo Valid HTML5 Logo HTML5 Logo Valid CSS3 Logo JGC Logo
Copyright logo
This page (jargonm.html) was last modified on Sunday 27/01/2013