Why V7 Unix matters so much

When I talk about things involving the history of Unix, I often wind up mentioning V7, also known as Seventh Edition of Research Unix from Bell Labs (for a recent example, in my entry on when Unix got stack size limits). If you're relatively new to the history of Unix, you might wonder why V7 keeps coming up so often. There are a number of reasons that V7 matters so much both for the history of Unix and for what is what we think of as being Unix' and the Unix way.

The history of Unix is... Complicated.