V7M

(from the Wikipedia article)

Digital Equipment Corporation (DEC)'s first native UNIX product was V7M (for modified) or V7M11 for the PDP-11 and was based on version of Seventh Edition from Bell Labs. V7M was developed by DEC's original Unix Engineering Group (UEG), Fred Canter, Jerry Brenner, Armando Stettner, Bill Burns, Mary Anne Cacciola and Bill Munson, but was primarily the work of Fred and Jerry.

V7M contained many fixes to the kernel including support for separate instruction and data spaces, significant work for hardware error recovery, and many device drivers. Much work was put into producing a release that would reliably bootstrap from many tape drives or disk drives. V7M was well respected in the Unix community. UEG evolved into the group that later developed Ultrix.

The files here come from the V7M area of the Unix Archive, and were donated by Jean Huens.