The Jargon File, Version 2.9.10, 01 Jul 1992. Various

Read-Only Memories (PROMs) that preceded present-day Erasable Programmable Read-Only Memories (EPROMs) involved intentionally blowing tiny electrical fuses on the chip. Thus, one was said to `blow' (or `blast') a PROM, and the terminology carried over even though the write process on EPROMs is nondestructive.

      :blow away: vt. To remove (files and directories) from permanent

       storage, generally by accident. "He reformatted the wrong

       partition and blew away last night's netnews." Oppose {nuke}.

      :blow out: vi. Of software, to fail spectacularly; almost as

       serious as {crash and burn}. See {blow past}, {blow up},

       {die horribly}.

      :blow past: vt. To {blow out} despite a safeguard. "The server blew past the 5K reserve buffer."

      :blow up: vi. 1. [scientific computation] To become unstable. Suggests that the computation is diverging so rapidly that it will soon overflow or at least go {nonlinear}. 2. Syn. {blow out}.

      :BLT: /B-L-T/, /bl*t/ or (rarely) /belt/ n.,vt. Synonym for {blit}. This is the original form of {blit} and the ancestor of {bitblt}. It referred to any large bit-field copy or move operation (one resource-intensive memory-shuffling operation done on pre-paged versions of ITS, WAITS, and TOPS-10 was sardonically referred to as `The Big BLT'). The jargon usage has outlasted the {PDP-10} BLock Transfer instruction from which {BLT} derives; nowadays, the assembler mnemonic {BLT} almost always means `Branch if Less Than zero'.

      :Blue Book: n. 1. Informal name for one of the three standard

       references on the page-layout and graphics-control language

       {PostScript} (`PostScript Language Tutorial and Cookbook',

       Adobe Systems, Addison-Wesley 1985, QA76.73.P67P68, ISBN

       0-201-10179-3); the other two official guides are known as the

       {Green Book}, the {Red Book}, and the {White Book} (sense

       2). 2. Informal name for one of the three standard references on

       Smalltalk: `Smalltalk-80: The Language and its

       Implementation', David Robson, Addison-Wesley 1983, QA76.8.S635G64,

       ISBN 0-201-11371-63 (this is also associated with green and red

       books). 3. Any of the 1988 standards issued by the CCITT's

       ninth plenary assembly. Until now, they have changed color each

       review cycle (1984 was {Red Book}, 1992 would be {Green

       Book}); however, it is rumored that this convention is going to be

       dropped before 1992. These include, among other things, the

       X.400 email spec and the Group 1 through 4 fax standards. See also

       {{book titles}}.

      :Blue Glue: [IBM] n. IBM's SNA (Systems Network Architecture), an incredibly {losing} and {bletcherous} communications protocol widely favored at commercial shops that don't know any better. The official IBM definition is "that which binds blue boxes together." See {fear and loathing}. It may not be irrelevant that {Blue Glue} is the trade name of a 3M product that is commonly used to hold down the carpet squares to the removable panel floors common in {dinosaur pen}s. A correspondent at U. Minn. reports that the CS department there has about 80 bottles of the stuff hanging about, so they often refer to any messy work to be done as `using the blue glue'.

      :blue goo: n. Term for `police' {nanobot}s intended to prevent {gray goo}, denature hazardous waste, destroy pollution, put ozone back into the stratosphere, prevent halitosis, and promote truth, justice, and the American way, etc. See {{nanotechnology}}.

      :blue wire: [IBM] n. Patch wires added to circuit boards at the factory to correct design or fabrication problems. This may be necessary if there hasn't been time to design and qualify another board version. Compare {purple wire}, {red wire}, {yellow wire}.

      :blurgle: /bler'gl/ [Great Britain] n. Spoken {metasyntactic variable}, to indicate some text which is obvious from context, or which is already known. If several words are to be replaced, blurgle may well be doubled or trebled. "To look for something in several files use `grep string blurgle blurgle'." In each case, "blurgle blurgle" would be understood to be replaced by the file you wished to search. Compare {mumble}, sense 6.

      :BNF: /B-N-F/ n. 1. [techspeak] Acronym for `Backus-Naur Form', a metasyntactic notation used to specify the syntax of programming languages, command sets, and the like. Widely used for language descriptions but seldom documented anywhere, so that it must usually be learned by osmosis from other hackers. Consider this BNF for a U.S. postal address:

      <postal-address> ::= <name-part> <street-address> <zip-part>

      <personal-part> ::= <name> | <initial> "."

      <name-part> ::= <personal-part> <last-name> [<jr-part>] <EOL> | <personal-part> <name-part>

      <street-address> ::= [<apt>] <house-num> <street-name> <EOL>

      <zip-part> ::= <town-name> "," <state-code> <ZIP-code> <EOL>

      This translates into English as: "A postal-address consists of a name-part, followed by a street-address part, followed by a zip-code part. A personal-part consists of either a first name or an initial followed by a dot. A name-part consists of either: a personal-part followed by a last name followed by an optional `jr-part' (Jr., Sr., or dynastic number) and end-of-line, or a personal part followed by a name part (this rule illustrates the use of recursion in BNFs, covering the case of people who use multiple first and middle names and/or initials). A street address consists of an optional apartment specifier, followed by a street number, followed by a street name. A zip-part consists of a town-name, followed by a comma, followed by a state code, followed by a ZIP-code followed by an end-of-line." Note that many things (such as the format of a personal-part, apartment specifier, or ZIP-code) are left unspecified. These are presumed to be obvious from context or detailed somewhere nearby. See also {parse}. 2. The term is also used loosely for any number of variants and extensions, possibly containing some or all of the {regexp} wildcards such as `*' or `+'. In fact the example above isn't the pure form invented for the Algol-60 report; it uses `[]', which was introduced a few years later in IBM's PL/I definition but is now universally recognized. 3. In {{science-fiction fandom}}, BNF means `Big-Name Fan' (someone famous or notorious). Years ago a fan started handing out black-on-green BNF buttons at SF conventions; this confused the hacker contingent terribly.

      :boa: [IBM] n. Any one of the fat cables that lurk under the floor in a {dinosaur pen}. Possibly so called because they display a ferocious life of their own when you try to lay them straight and flat after they have been coiled for some time. It is rumored within IBM that channel cables for the 370 are limited to 200 feet because beyond that length the boas get dangerous —- and it is worth noting that one of the major cable makers uses the trademark `Anaconda'.

      :board: n. 1. In-context synonym for {bboard}; sometimes used even for USENET newsgroups. 2. An electronic circuit board (compare {card}).

      :boat anchor: n. 1. Like {doorstop} but more severe; implies that the offending hardware is irreversibly dead or useless. "That was a working motherboard once. One lightning strike later, instant boat anchor!" 2. A person who just takes up space.

      :BOF: /B-O-F/ or /bof/ n. Abbreviation for the phrase "Birds Of a Feather" (flocking together), an informal discussion group and/or bull session scheduled on a conference program. It is not clear where or when this term originated, but it is now associated with the USENIX conferences for UNIX techies and was already established there by 1984. It was used earlier than that at DECUS conferences, and is reported to have been common at SHARE meetings as far back as the early 1960s.

      :bogo-sort: /boh`goh-sort'/ n. (var. `stupid-sort') The archetypical perversely awful algorithm (as opposed to {bubble sort}, which is merely the generic *bad* algorithm). Bogo-sort is equivalent to repeatedly throwing a deck of cards in the air, picking them up at random, and then testing whether they are in order.