"In the case of the 1771 and 179x series it's possible to build a really ne <circuit I've seen but never tried to match, which uses the /TEST pin on th < <Sounds like an ideal candidate for reimplementation in a single chip <microcontroller. Did that many years ago using 8748, worked very good too as I could count the pulses then issue them out as a ramped rate so that the head was accelerated and decelerated to the track. Didn't make any difference for a few track move. Head movement that was about 15 tracks or more it was very noticeable. CP/M does a lot of seek to the directory track (usually track one or two) every time it writes an extent or closes/opens a file so decreases in seek time payed nicely. Allison