binary file



1. Base two. A number representation consisting of zeros and ones used by practically all computers because of its ease of implementation using digital electronics and Boolean algebra.

<file format>

2. binary file.


3. A description of an operator which takes two arguments. See also unary, ternary.

Last updated: 2005-02-21

binary coded decimal


(BCD, packed decimal) A number representation where a number is expressed as a sequence of decimal digits and then each decimal digit is encoded as a four-bit binary number (a nibble). E.g. decimal 92 would be encoded as the eight-bit sequence 1001 0010.

In some cases, the right-most nibble contains the sign (positive or negative).

It is easier to convert decimal numbers to and from BCD than binary and, though BCD is often converted to binary for arithmetic processing, it is possible to build hardware that operates directly on BCD.

[Do calculators use BCD?]

Last updated: 2001-01-27

Binary Compatibility Standard

<programming, standard>

(BCS) The ABI of 88open.

Last updated: 1997-07-03

binary counter

<electronics, hardware>

A digital circuit which has a clock input and a number of count outputs which give the number of clock cycles. The output may change either on rising or falling clock edges. The circuit may also have a reset input which sets all outputs to zero when asserted. The counter may be either a synchronous counter or a ripple counter.

Last updated: 1997-07-03

binary data

binary file

binary exponential backoff

An algorithm for dealing with contention in the use of a network. To transmit a packet the host sets a local parameter, L to 1 and transmits in one of the next L slots. If a collision occurs, it doubles L and repeats.

binary file

<file format>

Any file format for digital data that does not consist of a sequence of printable characters (text). The term is often used for executable machine code.

All digital data, including characters, is actually binary data (unless it uses some (rare) system with more than two discrete levels) but the distinction between binary and text is well established. On modern operating systems a text file is simply a binary file that happens to contain only printable characters, but some older systems distinguish the two file types, requiring programs to handle them differently.

A common class of binary files is programs in machine language ("executable files") ready to load into memory and execute. Binary files may also be used to store data output by a program, and intended to be read by that or another program but not by humans. Binary files are more efficient for this purpose because the data (e.g. numerical data) does not need to be converted between the binary form used by the CPU and a printable (ASCII) representation. The disadvantage is that it is usually necessary to write special purpose programs to manipulate such files since most general purpose utilities operate on text files. There is also a problem sharing binary numerical data between processors with different endianness.

Some communications protocols handle only text files, e.g. most electronic mail systems before MIME became widespread in about 1995. The FTP utility must be put into "binary" mode in order to copy a binary file since in its default "ascii" mode translates between the different newline characters used on the sending and receiving computers.

Confusingly, some word processor files, and rich text files, are actually binary files because they contain non-printable characters and require special programs to view, edit and print them.

Last updated: 2005-02-21

binary large object


(BLOB) A large block of data stored in a database, such as an image or sound file. A BLOB has no structure which can be interpreted by the database management system but is known only by its size and location.

Last updated: 1997-11-04

binary package


An archive file that contains all files and directories that must be installed in order to make a working installation of the program(s) included in the package, and the maintainer scripts necessary for the installation. A binary package is usually specific to a certain platform, in contrast to a source package.

Last updated: 2001-01-27

binary prefix


(Or "IEC prefix") A prefix used with a unit of data to mean multiplication by a power of 1024. Binary prefixes are most often used with "byte" (e.g. "kilobyte") but also with bit (e.g. "megabit").

For example, the term kilobyte has historically been used to mean 1024 bytes, and megabyte to mean 1,048,576 bytes. The multipliers 1024 and 1,048,576 are powers of 1024, which is itself a power of two (1024 = 2^10). It is this factor of two that gives the name "binary prefix".

This is in contrast to a decimal prefix denoting a power of 1000, which is itself a power of ten (1000 = 10^3). Decimal prefixes are used in science and engineering and are specified in widely adopted SI standards. Note that the actual prefix - kilo or mega - is the same, it is the interpretation that differs.

The difference between the two interpretations increases with each multiplication, so while 1000 and 1024 differ by only 2.4%, 1000^6 and 1024^6 differ by 15%.

The 1024-based interpretation of prefixes is often still used informally and especially when discussing the storage capacity of random-access memory. This has lead to storage device manufacturers being accused of false marketing for using the decimal interpretation where customers might assume the larger, historical, binary interpretation.

In an attempt to clarify the distinction, in 1998 the IEC specified that kilobyte, megabyte, etc. should only be used for powers of 1000 (following SI). They specified new prefixes for powers of 1024 containing "bi" for "binary": kibibyte, mebibyte, etc.; an idea originally propsed by IUPAC. IEC also specified new abbreviations Ki, Mi, etc. for the new prefixes. Many other standards bodies such as NIST, IEEE and BIPM support this proposal but as of 2013 its use is rare in non-technical circles.

Specific units of IEC 60027-2 A.2 and ISO/IEC 80000

 IEC prefix	   Representations	 	 Customary prefix
 Name  Symbol  Base 2  Base	 Base 10	 Name	Symbol
 	 	    1024	 (approx)
 kibi  Ki	   2^10	   1024^1	1.02x10^3	kilo	k, K
 mebi  Mi	   2^20	   1024^2	1.05x10^6	mega	M
 gibi  Gi	   2^30	   1024^3	1.07x10^9	giga	G
 tebi  Ti	   2^40	   1024^4	1.10x10^12	tera	T
 pebi  Pi	   2^50	   1024^5	1.13x10^15	peta	P
 exbi  Ei	   2^60	   1024^6	1.15x10^18	exa     E
 zebi  Zi	   2^70	   1024^7	1.18x10^21	zetta	Z
 yobi  Yi	   2^80	   1024^8	1.21x10^24	yotta	Y

Last updated: 2013-11-04

binary relation


A relation between two sets or between a set and itself.

A partial order is a binary relation on a set that satisfies certain criteria.

Last updated: 2019-08-31

binary search


A search algorithm which repeatedly divides an ordered search space in half according to how the required (key) value compares with the middle element.

The following pseudo-C routine performs a binary search return the index of the element of vector "thing[first..last]" equal to "target":

 if (target < thing[first] || target > thing[last])
   return NOT_FOUND;
 while (first < last)
   mid = (first+last)/2;	/* truncate to integer */
   if (target == thing[mid])
     return mid;
   if (target < thing[mid])
     last = mid-1;
     first = mid+1;
 if (target == thing[last])
   return last;
 return NOT_FOUND;

Last updated: 2003-01-14

Binary Synchronous Transmission


(Bisynch) An IBM link protocol, developed in the 1960 and popular in the 1970s and 1980s.

Binary Synchronous Transmission has been largely replaced in IBM environments with SDLC. Bisync was developed for batch communications between a System 360 computer and the IBM 2780 and 3780 Remote Job Entry (RJE) terminals. It supports RJE and on-line terminals in the CICS/VSE environment. It operates with EBCDIC or ASCII character sets. It requires that every message be acknowledged (ACK) or negatively acknowledged (NACK) so it has high transmission overhead. It is typically character oriented and half-duplex, although some of the bisync protocol flavours or dialects support binary transmission and full-duplex operation.

Last updated: 1997-01-07

binary tree

(btree) A tree in which each node has at most two successors or child nodes. In Haskell this could be represented as

 data BTree a = NilTree
 	     | Node a (BTree a) (BTree a)

See also balanced tree.

Last updated: 1994-11-29


Berkeley Internet Name Domain



A Novell Netware database that contains definitions for entities such as users, groups, and workgroups. The bindery allows the network supervisor to design an organised and secure operating environment based on the individual requirements of each of these entities.

The bindery has three components: objects, properties, and property data sets. Objects represent any physical or logical entity, including users, user groups, file servers. Properties are characteristics of each object (e.g. passwords, account restrictions, internetwork addresses). Property data sets are the values assigned to an entity's bindery properties.

[Netware Version 3.11 "Concepts" documentation (a glossary of Netware-related terms)].

Last updated: 1996-03-07

binding handle


An identifier representing the connection between a client and server. An association between client/server end-points and protocols.

Last updated: 1997-03-18

binding-time analysis


An analysis to identify sub-expressions which can be evaluated at compile-time or where versions of a function can be generated and called which are specialised to certain values of one or more arguments.

See partial evaluation.

Last updated: 1995-03-28


<file format>

A Macintosh format for representing a binary file using only printable characters. The file is converted to lines of letters, numbers and punctuation. Because BinHex files are simply text they can be sent through most electronic mail systems and stored on most computers. However the conversion to text makes the file larger, so it takes longer to transmit a file in BinHex format than if the file was represented some other way.

Filename extension: .hqx.

See also BinHex 4.0, uuencode.

[Encoding algorithm?]

Last updated: 1994-11-30

Binhex 4.0

<file format>

A seven bit wide representation of a Macintosh file with CRC error checking. Binhex 4.0 files are designed for communication of Mac files over long distance, possibly noisy, seven bit wide paths.

[Difference from other binhex formats?]

Last updated: 1996-09-17



Probably the fastest freely available C-emulated Prolog. BinProlog features:

logical and permanent global variables; backtrackable destructive assignment; circular term unification; extended DCGs (now built into the engine as "invisible grammars"); intuitionistic and linear implication based hypothetical reasoning; a Tcl/Tk interface.

Version 3.30 runs on SPARC/Solaris 2.x, SunOS 4.x; DEC Alpha 64-bit version; DEC MIPS; SGI MIPS; 68k - NeXT, Sun-3; IBM RS6000; HP PA-RISC (two variants); Intel 80386, Intel 486/Linux, MS-DOS, Microsoft Windows 3.1 (with DOS-extender go32 v1.10).

Multi-BinProlog is a multi-threaded Linda-style parallel extension to BinProlog for Solaris 2.3.

E-mail: Paul Tarau <[email protected]>.

Last updated: 1995-04-04

Nearby terms:

Bill GatesBill Joybinariesbinarybinary coded decimalBinary Compatibility Standard

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