B was the name of a programming language developed at Bell Labs. It is almost extinct, as it was replaced by the C language. It was mostly the work of Ken Thompson with contributions from Dennis Ritchie, and first appeared in 1969 or thereabouts. Bell Laboratories (also known as Bell Labs and formerly known as AT&T Bell Laboratories and Bell Telephone Laboratories) was the main research and development arm of the United States Bell System. ... C is a general-purpose, procedural, imperative computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. ... Ken Thompson Kenneth Thompson (born February 4, 1943) is a pioneer of computer science notable for his contributions to the development of the C programming language and the UNIX operating system. ... Dennis Ritchie Dennis MacAlistair Ritchie (born September 9, 1941) is a computer scientist notable for his influence on ALTRAN, B, BCPL, C, Multics, and Unix. ... For the Stargate SG-1 episode, see 1969 (Stargate SG-1). ...

History

B was essentially the BCPL system stripped of any component that Thompson felt he could do without, in order to make it fit within the memory capacity of the minicomputers of the time. The language also included some changes made to suit Thompson's preferences (mostly along the lines of reducing the number of non-whitespace characters in a typical program). BCPL (Basic Combined Programming Language) is a computer programming language that was designed by Martin Richards of the University of Cambridge in 1966; it was originally intended for use in writing compilers for other languages. ...

Like BCPL and FORTH, B had only one datatype, the computer word. Most operators treated this as an integer (i.e., +, -, *, /) but others treated it as a memory address to be dereferenced. In most other ways it looked a lot like an early version of C. A few library functions existed, including some that vaguely resemble functions from the standard IO library in C. Forth is a programming language and programming environment, initially developed by Charles H. Moore at the US National Radio Astronomy Observatory in the early 1970s. ...

Early implementations were for the DEC PDP-7 and PDP-11 minicomputers using early Unix, and Honeywell 36-bit mainframes running the operating system GCOS. The earliest PDP-7 implementations compiled to threaded code, then Ritchie wrote a compiler which produced machine code. In 1970 a PDP-11 was acquired and threaded code was used for the port. The first version of yacc was produced with this PDP-11 configuration. Ritchie took over maintenance during this period. The DEC logo Digital Equipment Corporation was a pioneering American company in the computer industry. ... A modified PDP-7 under restoration in Oslo, Norway The DEC PDP-7 is a minicomputer produced by Digital Equipment Corporation. ... The PDP-11 was a 16-bit minicomputer sold by Digital Equipment Corp. ... Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIX®) is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ... Honeywell Heating Specialties Company Stock Certificate dated 1924 signed by Mark C. Honeywell - courtesy of Scripophily. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... In computer science, the term threaded code refers to an implementation technique for programming languages that produces very compact code. ... The PDP-11 was a 16-bit minicomputer sold by Digital Equipment Corp. ... Yacc is a piece of computer software that serves as the standard parser generator on Unix systems. ...

The typeless nature of B made sense on the Honeywell, PDP-7 and many older computers, but was a problem on the PDP-11 because it was difficult to elegantly access the character data type that the PDP-11 and most modern computers fully support. Starting in 1971 Ritchie made changes to the language while converting its compiler to produce machine code, most notably adding data typing for variables. During 1971 and 1972 B evolved into "New B" and then C, with the preprocessor being added in 1972 and early 1973 at the urging of Alan Snyder. The effort was sufficiently complete that during the summer of 1973 the Unix kernel for the PDP-11 was rewritten in C. During the 1972-73 period there was a need to port to Honeywell 635 and IBM 360/370 machines, so Mike Lesk wrote the "portable I/O package" which would become the C "standard I/O" routines. In computer science, a preprocessor is a program that processes its input data to produce output that is used as input to another program. ... Mike Lesk is a computer program writer who created the lex programming tool, a program for Unix computers, with Eric E. Schmidt. ...

B continued to see use as late as the 1990s on Honeywell mainframes, and on certain embedded systems for a variety of reasons, including limited hardware in the small systems; extensive libraries, tools, licensing cost issues; and simply being good enough for the job on others. The highly influential AberMUD was written in B. What is an Embedded System? Electronic devices that incorporate a computer(usually a microprocessor) within their implementation. ... AberMUD was the first popular internet-based MUD. The first version was written in B by Alan Cox for an old Honeywell mainframe and opened in 1987. ...

B was greatly influenced by BCPL, and its name is most likely to be a contraction of BCPL. However it is possible that its name may be based on Bon, an earlier but unrelated, and rather different, programming language which Thompson designed for use on Multics.^{[citation needed]} Bon was a programming language created by Ken Thompson while he worked on the MULTICS operating system. ... Multics (Multiplexed Information and Computing Service) was an extraordinarily influential early time-sharing operating system. ...

Example

The following example is from the Users' Reference to B by Ken Thompson:

 /* The following function will print a non-negative number, n, to the base b, where 2<=b<=10, This routine uses the fact that in the ASCII character set, the digits 0 to 9 have sequential code values. */ printn(n,b) { extrn putchar; auto a; if(a=n/b) /* assignment, not test for equality */ printn(a, b); /* recursive */ putchar(n%b + '0'); } 

External links

• The Development of the C Language, Dennis M. Ritchie. Puts B in the context of BCPL and C.
• Users' Reference to B, Ken Thompson. Describes the PDP-11 version.
• The Programming Language B, S. C. Johnson & B. W. Kernighan, Technical Report CS TR 8, Bell Labs (January 1973). The GCOS version on Honeywell equipment.

Dennis Ritchie Dennis MacAlistair Ritchie (born September 9, 1941) is a computer scientist notable for his influence on ALTRAN, B, BCPL, C, Multics, and Unix. ... BCPL (Basic Combined Programming Language) is a computer programming language that was designed by Martin Richards of the University of Cambridge in 1966; it was originally intended for use in writing compilers for other languages. ... C is a general-purpose, procedural, imperative computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. ... The PDP-11 was a 16-bit minicomputer sold by Digital Equipment Corp. ... Bell Laboratories (also known as Bell Labs and formerly known as AT&T Bell Laboratories and Bell Telephone Laboratories) was the main research and development arm of the United States Bell System. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Honeywell Heating Specialties Company Stock Certificate dated 1924 signed by Mark C. Honeywell - courtesy of Scripophily. ...

See also

• The B-Method, a formal method with its own Abstract Machine Notation (AMN), not to be confused with the B programming language.

Another language, also called B, was a simple interactive programming language by Lambert Meertens and Steven Pemberton. This B was the predecessor of ABC. B is a tool-supported formal method based around AMN (Abstract Machine Notation), used in the development of computer software. ... In computer science, formal methods refers to a variety of scientific and engineering techniques for rigorous reasoning about the correctness of computer programs, chiefly based on the use of mathematical logic. ... Abstract Machine Notation (AMN) is a programming language for specifying abstract machines in the B-Method, based on the mathematical theory of Generalised Substitutions. ... ABC is an imperative general-purpose programming language and programming environment from CWI, Netherlands. ...

Draft Proposal for the B Programming Language, Lambert Meertens, CWI, Amsterdam, 1981. (No longer available as of 30 December 2004.)