Just patting myself on the back...

[Bill E]

Sorry. I've been doing some timing tests and such to be sure things haven't broken. Timed the drum. DEC says 'approximately' 35 msec for a full 4096 word track transfer. Timed mine. 34.816 msecs, which also happens to be exactly the value you get if you look at the original drum timing of 8.5 usec/word. Not bad if I do say so myself. :)

OTOH, the individual per-word time isn't quite accurate, 8.5usec is not a convenient multiple of the 5usec cycle time, it's only exact every multiple of 17 words. But, this internal timing isn't visible, it's just annoying to me. Aap would not be happy. But, the overall time is exact for any word count and is the delay you will get doing an IOT i or c.

Bill