Bryan Parkoff wrote:
If the nominal delay between consecutive 1 bits is 4 uS at 300 RPM, it will be 4 * 300 / 280 =~ 4.29 uS and 4 * 300 / 320 = 3.75 uS at 320 RPMWhere did you get "4"? It looks like that the disk spins from 0 degree to 359 degree five time each 1 second. RPM stands for rotation per minute. You multiply 5 rotation by 60 seconds and it equals to 300 RPM. How do you get microsecond?
By knowing (or reading) that the data rate that was 250 K bits per sec. for all (?) the 5.25" disks before the "high-density" 1.2 MB ones.
Just about every Apple 2 reference mentions this fact too.
Bryan Parkoff