On Thu, 5 Feb 2009, dwight elvey wrote: > Hi > The plan was to use a 3.5 disk on a H89 or N*, not read them > on a PC. Some of the older drives had a flywheel. A drill, in indexing jig, a light and photocell, any you could modify a 3.5" drive to provide 10 or 16 pulses from physically fixed positions, without being dependent on repeatability of rotational speed.