-----Original Message----- From: Jon Elson <el...@pico-systems.com> <snip> >>>> I have two SPST time delay 12-volt relays packaged like vacuum >>>> tubes with octal bases, Amperite models 12N010 (ten seconds) and >>>> 12C5 (five seconds). >>>> >> Another place they were used (but I think 60 second >> delay) was in the IBM 2314 disk system, where these delayed loading >> the heads until the drive had been spinning for 60 seconds or so. >> >> Jon >> > Now that's an actual antique computer application, though I'm > surprised they didn't use a solid state implementation. > > Bob > 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. Jon Comment-------------------------------------- I wouldn't call the 2314 low tech - it was the highest areal density at the time, a breakthru with ferrite heads and very low cost to manufacture. Note I said cost, its profit margin was enormous, in part by putting as much expensive electronics as possible in the control unit. 😊 Actually the 2314 did not ship with the first 360's in 1965; it was announced in April 1965 about 1 year after the 360 announcement and AFAICT from Bitsavers document dates it didn't ship until late 1966, which FWIW, at the Computer History Museum, 1966 is also the date for first shipment of the 2414 and its ferrite heads. BTW the hydraulic actuator design goes back to the 1311 - more or less the same actuator in the 1311, 2311 and 2314. Tom
