Online Computer Terms Dictionary - B

brace

<character> left brace or right brace.

bracket

<character> (Or square bracket) A left bracket or right bracket.

Often used loosely for parentheses, square brackets, braces, angle brackets, or any other kind of unequal paired delimiters.

(1996-09-08)

bracket abstraction

<compiler> An algorithm which turns a term into a function of some variable. The result of using bracket abstraction on T with respect to variable v, written as [v]T, is a term containing no occurrences of v and denoting a function f such that f v = T. This defines the function f = (\ v . T). Using bracket abstraction and currying we can define a language without bound variables in which the only operation is monadic function application.

See combinator.

(1995-03-07)

braille

<human language> /breyl/ (Often capitalised) A class of writing systems, intended for use by blind and low-vision users, which express glyphs as raised dots. Currently employed braille standards use eight dots per cell, where a cell is a glyph-space two dots across by four dots high; most glyphs use only the top six dots.

Braille was developed by Louis Braille (pronounced /looy bray/) in France in the 1820s. Braille systems for most languages can be fairly trivially converted to and from the usual script.

Braille has several totally coincidental parallels with digital computing: it is binary, it is based on groups of eight bits/dots and its development began in the 1820s, at the same time Charles Babbage proposed the Difference Engine.

Computers output Braille on braille displays and braille printers for hard copy.

British Royal National Institute for the Blind.

(1998-10-19)

braille display

<hardware> (Or "refreshable braille display", "refreshable display") An electromechanical device that renders braille with tiny, independently controlled pins used to represent the state of dots in braille cells. Each pin, in its "on" state, raises above the top of its hole in the screen; in its "off" state, it drops below the top of its hole. Older systems used tiny solenoids to control the state of the pins; modern systems are piezoelectric.

Typical dimensions of a braille display are 1 line of 40 cells, each cell of two-by-eight dots.

(1998-10-19)

Braille embosser

Braille printer

Braille printer

<printer> (Or "(Braille) embosser") A printer, necessarily an impact printer, that renders text as Braille. Blind users call other printers ink printers.

(1999-02-26)

Brain Aid Prolog

<language> (BAP) A parallel Prolog environment for transputer systems by Frank Bergmann <fraber@fraber.de>, Martin Ostermann <ost@xan.dfv.rwth-aachen.de>, and Guido von Walter <guido@parsytec.de> of Brain Aid Systems GbR. BAP is based on a model of communicating sequential Prolog processes. The run-time system consists of a multi-process operating system with support for several applications running concurrently.

Home.

(2002-11-12)

brain-damaged

1. [generalisation of "Honeywell Brain Damage" (HBD), a theoretical disease invented to explain certain utter cretinisms in Honeywell Multics] Obviously wrong; cretinous; demented. There is an implication that the person responsible must have suffered brain damage, because he should have known better. Calling something brain-damaged is really bad; it also implies it is unusable, and that its failure to work is due to poor design rather than some accident. "Only six monocase characters per file name? Now *that's* brain-damaged!"

2. [especially in the Mac world] May refer to free demonstration software that has been deliberately crippled in some way so as not to compete with the commercial product it is intended to sell. Synonym crippleware.

[Jargon File]

brain-dead

Brain-damaged in the extreme. It tends to imply terminal design failure rather than malfunction or simple stupidity.

brain dump

(The act of telling someone) everything one knows about a particular topic. Typically used when someone is going to let a new party maintain a piece of code. Conceptually analogous to an operating system core dump in that it saves a lot of useful state before an exit. "You'll have to give me a brain dump on FOOBAR before you start your new job at HackerCorp." At Sun, this is also known as "TOI" (transfer of information).

[Jargon File]

brain fart

<jargon, humour> 1. The actual result of a braino, as opposed to the mental glitch that is the braino itself. E.g. typing "dir" on a Unix box after a session with MS-DOS.

2. A biproduct of a bloated mind producing information effortlessly. A burst of useful information. "I know you're busy on the Microsoft story, but can you give us a brain fart on the Mitnik bust?"

(1997-04-29)

Brainfuck

<language> An eight-instruction programming language created by Urban Müller. His goal was apparently to create a Turing-complete language with the smallest compiler ever, for the Amiga OS 2.0. He eventually reduced his compiler to under 200 bytes.

A Brainfuck program has a pointer that moves within an array of 30000 bytes, initially all set to zero. The pointer initially points to the beginning of this array. The language has eight commands, each of which is represented as a single character, and which can be expressed in terms of C as follows:

 >   ==>    ++p;
 <   ==>    --p;
 +   ==>    ++*p;
 -   ==>    --*p;
 .   ==>    putchar(*p);
 ,   ==>    *p = getchar();
 [   ==>    while (*p) {
 ]   ==>    }

(2003-11-18)

braino

thinko

branch

1. <mathematics> An edge in a tree.

2. <programming> A jump.

Branch and Hang

<humour> (BRH) Originally a mythical instruction for the IBM 1130 at Indiana University.

Later some real examples were discovered. The Texas Instruments TI-980 allowed all addressing modes with all instructions, including Store Immediate Extended (stores the value into the extension word of the instruction) and Branch and Link Immediate (makes a subroutine call to the same instruction -- Branch and Hang).

Compare HCF.

(1997-02-12)

branch coverage testing

<programming> A test method which aims to ensure that each possible branch from each decision point (e.g. "if" statement) is executed at least once, thus ensuring that all reachable code is executed.

(1996-05-10)

branch delay slot

delayed control-transfer

Branch on Chip Box Full

<humour> (BCBF) A mythical IBM 1130 instruction whose action depended on the contents of the chip box. This was one of a long list of fake assembly language instructions that went around Indiana University in the 1970s.

(1997-02-12)

branch prediction

<processor, algorithm> A technique used in some processors with instruction prefetch to guess whether a conditional branch will be taken or not and prefetch code from the appropriate location.

When a branch instruction is executed, its address and that of the next instruction executed (the chosen destination of the branch) are stored in the Branch Target Buffer. This information is used to predict which way the instruction will branch the next time it is executed so that instruction prefetch can continue. When the prediction is correct (and it is over 90% of the time), executing a branch does not cause a pipeline break.

Some later CPUs simply prefetch both paths instead of trying to predict which way the branch will go.

An extension of the idea of branch prediction is speculative execution.

(1998-03-14)

Branch Target Buffer

<processor> (BTB) A register used to store the predicted destination of a branch in a processor using branch prediction?

[Is this correct? Examples?]

(1995-05-05)

branch to Fishkill

(IBM: from the location of one of the corporation's facilities) Any unexpected jump in a program that produces catastrophic or just plain weird results.

See jump off into never-never land, hyperspace.

[Jargon File]

Brazil

An operating system from Acorn Computers used on an ARM card which could be fitted to an IBM PC. There was also an ARM second processor for the BBC Microcomputer which used Brazil. Never used on the Archimedes(?).

(1994-12-05)