The inception of C and it's intertwinedness with the UNIX operating system, the predecessor to Linux

[sorcerer_see]

"I did the first of two or three versions of UNIX all alone. And Dennis (Ritchie) became an evangelist. Then there was a rewrite in a higher-level language that would come to be called C. He worked mostly on the language and on the I/O system, and I worked on all the rest of the operating system. That was for the PDP-11, which was serendipitous, because that was the computer that took over the academic community." Kenneth Thompson, about the events in 1972-73 that have caused the C programming language, created by Dennis Ritchie, and the birth of Linux 20 years later.

Left: Dennis Ritchie (UNIX and the C language), Right: Kenneth Thompson (UNIX and the B language)

The DP11. The computer for which Dennis & Ken adapted UNIX to be written in a new language called C, which was based on B.