Carl D. Howe. program to measure 810 disk speed. The following is my DSKRPM program that I described in a previous message. It is not entirely deterministic; I assume that this is because of heterodyning between BASIC execution and the disk rotation. However, I have not really verified this fact; if anyone has any ideas any ideas, please let me know. P.S. The proper number to get is about 292 RPM.