On 10/1/24 07:54, Jon Elson via cctalk wrote: > The IBM 2314 was REALLY low tech. There was almost no electronics in > the drives! They has a read amp, a write amp and a hydraulic "stepper > motor" with mechanical detents that moved the heads in response to step > in and step out pulses from the control unit. > > IBM did know how to distill things down to the absolute minimum. > Remember, this was developed in the early 1960s and first shipped with > the first 360's in 1965.
Hydraulic positioning was used in several early drives. The Bryant 4000/CDC 6603, for example, had containers to catch leaks. ISTR that the head assemblies weighed about 8 lbs each. The Univac FASTRAND drum, on the other hand, used electromagnetic positioning, employing a mechanical lever adder to come up with a binary position. -C
