Белл Лабораториясында жасалған B бағдарламалау тілі

Procedural programming language
a programming language developed at Bell Labs

B is a programming language developed at Bell Labs circa 1969 by Ken Thompson and Dennis Ritchie. B was derived from BCPL, and its name may possibly be a contraction of BCPL. Thompson's coworker Dennis Ritchie speculated that the name might be based on Bon, an earlier, but unrelated, programming language that Thompson designed for use on Multics. B was designed for recursive, non numeric, machine independent applications, such as system and language software. It was a typeless language, with the only data type being the underlying machine's natural memory word format, whatever that might be. Depending on the context, the word was treated either as an integer or a memory address. As machines with ASCII processing became common, notably the DEC PDP 11 that arrived at Bell Labs, support for character data stuffed in memory words became important. The typeless nature of the language was seen as a disadvantage, which led Thompson and Ritchie to develop an expanded version of the language supporting new internal and user defined types, which became the C programming language.

Circa 1969, Ken Thompson Thompson went further by inventing the increment and decrement operators (++ and ). Their prefix or postfix position determines whether the value is taken before or after alteration of the operand. This innovation was not in the earliest versions of B. According to Dennis Ritchie, people often assumed that they were created for the auto increment and auto decrement address modes of the DEC PDP 11, but this is historically impossible as the machine didn't exist when B was first developed. B is typeless, or more precisely has one data type: the computer word. Most operators (e. g. +, , *, /) treated this as an integer, but others treated it as a memory address to be dereferenced. In many other ways it looked a lot like an early version of C. There are a few library functions, including some that vaguely resemble functions from the standard I/O library in C. 36 bit mainframes running the operating system GCOS. The earliest PDP 7 implementations compiled to threaded code, and Ritchie wrote a compiler using TMG which produced machine code. In 1970 a PDP 11 was acquired and threaded code was used for the port; an assembler, , and the B language itself were written in B to bootstrap the computer. An early version of yacc was produced with this PDP 11 configuration. Ritchie took over maintenance during this period. and on certain embedded systems (as of 2000) for a variety of reasons: limited hardware in small systems, extensive libraries, tooling, licensing cost issues, and simply being good enough for the job. The highly influential AberMUD was originally written in B.