Re: [TUHS] pdp11 question

Wilko Bulte wrote: Unfortunately a few things on that page are inaccurate. For example, it's not exactly a PDP-11/83, it's really a microPDP-11/73, although the memory has been rearranged as the writer stated. Both microPDP-11/73 and /83 use KDJ11-B, the difference being that the /73 used 15MHz parts (as in that one) and the /83s which came later had 18MHz parts, and more importantly they have different boot ROMs. However the other and arguably most important difference between /73 and /83 systems is that the /73s were originally set up with a normal QBus memory configuration, whereas /83s use PMI memory with the memory in front of the CPU instead of behind it. The boards in this one have been re-ordered, and although having the CPU for a microPDP-11/73 it will mostly behave as a slightly-slow /83. KDJ11-A boards were used as upgrades for rack-based 11/23s and OEM systems, not microPDP-11s. So the one on that page is close to its original configuration, except for the Dilog SCSI controller and the memory arrangement. -- Pete Peter Turnbull Network Manager University of York