-----Original Message-----
From: Jon Elson <elson(a)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