: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}. These problems were severe on older machines with small, fixed-size address spaces, and special "leak detection" tools were commonly written to root them out. With the advent of virtual memory, it is unfortunately easier to be sloppy about wasting a bit of memory (although when you run out of memory on a VM machine, it means you've got a *real* leak!). See {aliasing bug}, {fandango on core}, {smash the stack}, {precedence lossage}, {overrun screw}, {leaky heap}, {leak}.
:memory smash: [XEROX PARC] n. Writing through a pointer that doesn't point to what you think it does. This occasionally reduces your machine to a rubble of bits. Note that this is subtly different from (and more general than) related terms such as a {memory leak} or {fandango on core} because it doesn't imply an allocation error or overrun condition.
: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 metasyntactic 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 {{Humor, 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}.
Historical note: although in modern usage shaped by a universe of 8-bit bytes the meta bit is invariably hex 80 (octal 0200), things were different on earlier machines with 36-bit words and 9-bit bytes. The MIT and Stanford keyboards (see {space-cadet keyboard}) generated hex 100 (octal 400) from their meta keys.
:metasyntactic variable: n. A name used in examples and understood to stand for whatever thing is under discussion, or any random member of a class of things under discussion. The word {foo} is the {canonical} example. To avoid confusion, hackers never (well, hardly ever) use `foo' or other words like it as permanent names for anything. In filenames, a common convention is that any filename beginning with a metasyntactic-variable name is a {scratch} file that may be deleted at any time.
To some extent, the list of one's preferred metasyntactic variables is a cultural signature. They occur both in series (used for related groups of variables or objects) and as singletons. Here are a few common signatures:
{foo}, {bar}, {baz}, {quux}, quuux, quuuux…:
MIT/Stanford usage, now found everywhere (thanks largely to early
versions of this lexicon!). At MIT, {baz} dropped out of use for
a while in the 1970s and '80s. A common recent mutation of this
sequence inserts {qux} before {quux}.
{foo}, {bar}, thud, grunt:
This series was popular at CMU. Other CMU-associated variables
include {gorp}.
{foo}, {bar}, fum:
This series is reported common at XEROX PARC.
{fred}, {barney}:
See the entry for {fred}. These tend to be Britishisms.
{toto}, titi, tata, tutu:
Standard series of metasyntactic variables among francophones.
{corge}, {grault}, {flarp}:
Popular at Rutgers University and among {GOSMACS} hackers.
zxc, spqr, {wombat}:
Cambridge University (England).