Unix – History and Architecture

You might have asked yourself why there should be a chapter about Unix in the middle of a book about expert-level C. If you have not, I invite you to ask yourself, how can these two topics, C and Unix, be related in such a way that there's a need for two dedicated chapters (this and the next chapter) in the middle of a book that should talk about C?

The answer is simple: if you think they are unrelated, then you are making a big mistake. The relationship between the two is simple; Unix is the first operating system that is implemented with a fairly high-level programming language, C, which is designed for this purpose, and C got its fame and power from Unix. Of course, our statement about C being a high-level programming language is not true anymore, and C is no longer considered to be so high-level.

Back in the 1970s and 1980s, if the Unix engineers at Bell Labs had decided to use another programming language, instead of C, to develop...