The C programming language will turn fifty years old in 2022. Yet despite its long history, C remains one of the top "most-used" programming languages in many "popular programming languages" surveys. For example, check out the TIOBE Index, which tracks the popularity of different programming languages. Many Linux applications are written in C, such as the GNOME desktop.
I interviewed Brian Kernighan, co-author (with Dennis Ritchie) of The C Programming Language book, to learn more about the C programming language and its history.
Where did the C programming language come from?
C is an evolution of a sequence of languages intended for system programming—that is, writing programs like compilers, assemblers, editors, and ultimately operating systems. The Multics project at MIT, with Bell Labs as a partner, planned to write everything in a high-level language (a new idea at the time, roughly 1965). They were going to use IBM's PL/1, but it was very complicated, and the promised compilers didn't arrive in time.
After a brief flirtation with a subset called EPL (by Doug McIlroy of Bell Labs), Multics turned to BCPL, a much simpler and cleaner language designed and implemented by Martin Richards of Cambridge, who I think was visiting MIT at the time. When Ken Thompson started working on what became Unix, he created an even simpler language, based on BCPL, that he called B. He implemented it for the PDP-7 used for the first proto-Unix system in 1969.
BCPL and B were both "typeless" languages; that is, they had only one data type, integer. The DEC PDP-11, which arrived on the scene in about 1971 and was the computer