In the 1960s, Bell Labs (AT&T) employees began working on a project called Multics. The purpose of this project was to develop an operating system for a large computer that could be used by a thousand users. Bell Labs withdrew from the project in 1969 because the project failed to produce an economically viable system. So Bell Labs employees had to look for another project to work on AT&T.

Ken Thompson began work on the development of a new file system. DEC wrote assembler a version of the new file system for the PDP-7. After a short time, they started making improvements and additions. They used information from the Multics project for these improvements. After a while, a complete system was born.

It was also called the UNIX system, making a mocking reference to Multics. The whole system was still written in assembly code.

This situation (assembly code) was introducing some problems. You had to write many code pages to accomplish a certain task.

To overcome this problem, they started to use the B language here. B solved this problem. Unlike assembly language, B needed significantly fewer lines of code to execute a task in UNIX. The B language was created by Ken Thompson in 1970 using many features of the BCPL (Basic Combined Programming Language).

Still, there was much that B couldn't do. B did not recognize datatypes. Even with B, data types were expressed in machine language. B also did not support data structures. Much more was expected from B in the context of rapidly changing requirements.

Something had to change. Dennis Ritchie and his colleagues developed the C language in 1972. In fact, the deficiencies in the B language were corrected and it was translated into the C language. While many features in B language are preserved, data types and data structures that are not in B language have been added.

The C language now had powerful high-level functionality and the detailed features needed to program an operating system.

Most of its components in the UNIX operating system were rewritten in C. UNIX is still one of the most popular network operating systems in use today.

Over time, the C language has been improved and rich features have been added. Memory management, functions, classes and libraries are some of them. C is used in the world's largest and most exclusive projects and products. It has also influenced the development of many languages such as C, AMPL, AWK, csh, C++, C--, C#, Bit C, D, Go, Java, JavaScript, Julia, Limbo, LPC, Perl, PHP, Python.

Almost all major operating systems nowadays are written in C and C++. Microsoft Windows development has mostly been on C. Developed in C on macOS, Linux, Android, iOS and Windows Phone. Almost all modern operating systems are based on C. Systems in vehicles, IoT (Internet of Things?), smart TVs also benefited from C.