An interesting article on the early versions of Unix can be found online at:
   http://www.daemonnews.org/199903/history.html
The arrtcle, which is an slightly updated version originally published in
Microsystems in 1984, is titled:
   A History of UNIX Before Berkeley: UNIX® Evolution, 1975-1984
   by Ian F. Darwin and Geoffrey Collyer

Martin Crehan