The C programming language was devised in the early 1970s by Dennis M. Ritchie an employee from Bell Labs (AT&T).
In the 1960s Ritchie worked, with several other employees of Bell
Labs (AT&T), on a project called Multics. The goal of the project
was to develop an operating system for a large computer that could be
used by a thousand users. In 1969 AT&T (Bell Labs) withdrew from the
project, because the project could not produce an economically useful
system. So the employees of Bell Labs (AT&T) had to search for
another project to work on (mainly Dennis M. Ritchie and Ken Thompson).
Ken Thompson began to work on the development of a new file system.
He wrote, a version of the new file system for the DEC PDP-7, in
assembler. (The new file system was also used for the game Space
Travel). Soon they began to make improvements and add expansions. (They
used there knowledge from the Multics project to add improvements).
After a while a complete system was born. Brian W. Kernighan called the
system UNIX, a sarcastic reference to Multics. The whole system was
still written in assembly code.
Besides assembler and Fortran, UNIX also had an interpreter for the
programming language B. ( The B language is derived directly from Martin
Richards BCPL). The language B was developed in 1969-70 by Ken
Thompson. In the early days computer code was written in assembly code.
To perform a specific task, you had to write many pages of code. A
high-level language like B made it possible to write the same task in
just a few lines of code. The language B was used for further
development of the UNIX system. Because of the high-level of the B
language, code could be produced much faster, then in assembly.
A drawback of the B language was that it did not know data-types.
(Everything was expressed in machine words). Another functionality that
the B language did not provide was the use of “structures”. The lag of
these things formed the reason for Dennis M. Ritchie to develop the
programming language C. So in 1971-73 Dennis M. Ritchie turned the B
language into the C language, keeping most of the language B syntax
while adding data-types and many other changes. The C language had a
powerful mix of high-level functionality and the detailed features
required to program an operating system. Therefore many of the UNIX
components were eventually rewritten in C (the Unix kernel itself was
rewritten in 1973 on a DEC PDP-11).
The programming language C was written down, by Kernighan and
Ritchie, in a now classic book called “The C Programming Language, 1st
edition”. (Kernighan has said that he had no part in the design of the C
language: “It’s entirely Dennis Ritchie’s work”. But he is the author
of the famous “Hello, World” program and many other UNIX programs).
For years the book “The C Programming Language, 1st edition” was the standard on the language C. In 1983 a committee was formed by the American National Standards Institute (ANSI)
to develop a modern definition for the programming language C (ANSI
X3J11). In 1988 they delivered the final standard definition ANSI C.
(The standard was based on the book from K&R 1st ed.).
The standard ANSI C made little changes on the original design of the
C language. (They had to make sure that old programs still worked with
the new standard). Later on, the ANSI C standard was adopted by the
International Standards Organization (ISO). The correct term should
there fore be ISO C, but everybody still calls it ANSI C.
copy from : www.codingunit.com
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