(Although if you want to run the original Unix v6, written in a now-archaic proto-C --- unsigned integer variables are declared as pointers because "unsigned" itself wasn't directly supported in the language yet --- PDP-11 emulators and system images are readily available.)
Comments
Might also be worth looking at xv6, which is a rewrite of Unix v6 in modern C, and comes with an exegesis modelled on the classic Lions book:
http://pdos.csail.mit.edu/6.828/2012/xv6.html
(Although if you want to run the original Unix v6, written in a now-archaic proto-C --- unsigned integer variables are declared as pointers because "unsigned" itself wasn't directly supported in the language yet --- PDP-11 emulators and system images are readily available.)