Hi Ross, you'll find on the Bitsavers Site (http://www.bitsavers.org) lots of documents, some handbooks under http://www.bitsavers.org/pdf/dec/pdp11/handbooks/ and the "PDP-11 Processor Handbook - PDP11/04/34a/44/60/70" under http://www.bitsavers.org/pdf/dec/pdp11/handbooks/PDP11_Handbook1979.pdf Under http://www.bitsavers.org/pdf/dec/pdp11 is quite a bit on various pdp-11 models, for example the "KB11-C Processor Manual (PDP-11/70)" http://www.bitsavers.org/pdf/dec/pdp11/1170/EK-KB11C-TM-001_1170procMan.pdf in case you'd like to go into details :). With best regards, Walter -- Dr. Walter F.J. Müller Mail: W.F.J.Mueller(a)gsi.de GSI, Abteilung KP3 Phone: +49-6159-71-2766 D-64291 Darmstadt FAX: +49-6159-71-3762 URL: http://www-linux.gsi.de/~mueller/