By Vern Strong of Technical Support
Fourth Printing April 1973
This is believed to relate to a PDP system from Digital probably the PDP-11 series based on the date.
This is a very comprehensive manual which also includes hand written notes and sketches from that time.

This was very kindly donated by David Hext

Reference Number / ISBN :

Date Published : April 1973
Publisher : Digital Equiptment Limited
Format : Small format comb binding