On Apr 5, 2022, at 8:07 AM, Noel Chiappa via cctalk <cctalk at classiccmp.org> wrote: So, I looked at the early editions of the "pdp11 peripherals hanbook", which have good, detailed discussions of UNIBUS operations (at the back; chapter 5, "UNIBUS Theory and Operation", in the 1976 edition), but in contrast to the level of detail given for master/slave operations, and bus requests and interrupts, the level of detail on power up/down is very low, especially compared to that in the later "pdp11 bus hanbook" (which, as mentioned, does not seem to be online yet, alas). So, I have transcribed that section, and posted it: https://gunkies.org/wiki/UNIBUS_Initialization I have yet to scan and post the associated timing diagrams (which are useful, but not critical); the desktop that runs my scanner is down at the moment, alas. (If anyone who has a copy would like to volunteer to scan them, that would be great.) Noel