> take rotation into account. ... > I don't think that there were any drives that would tell you this Old MFM/RLL drives would not only tell you this, they'

> take rotation into account. ... > I don't think that there were any drives that would tell you this Old MFM/RLL drives would not only tell you this, they'd let you alter it during the low-level format procedure. There was a parameter called "sector interleave" that would let you deliberately stagger the sector spacing, so it would be like 1,14,2,15,3,16,4,17,5,18,6,19,7,20,8,21,9,22,10,23,11,24,12,25,13,26 or something. This was because controllers didn't do caching yet, and PIO mode and CPUs of the era were so slow they couldn't necessarily keep up with data coming off at the full rotation rate. If you missed the start of the next sector, you had to wait a whole rev for it to come around again, a nearly-26x slowdown. Whereas a 2:1 interleave would virtually guarantee that you'd be ready in time for the next sector, for only a 2x slowdown. (Really crap machines could even need a 3:1 interleave, the horrors!)