Disk drive 50 years old today (305 RAMAC)

Brent Hilpert hilpert at cs.ubc.ca
Thu Sep 14 15:40:50 CDT 2006

Chuck Guzis wrote:
> On 9/14/2006 at 12:19 PM woodelf wrote:
> >Segment from BRL - report #1115 march 1961.
> ...
> >     2D21            205
> ...
> Most likely coil drivers for punch/printer/relays?

I have seen them used in digital applications for purposes other than driving
electro-mechanical stuff, however. Specifically, as the reset drivers in an HP
524 tube counter (resetting the string of counter flip-flops). I suspect the low
plate ('ON') resistance was the attraction/benefit.

(The 2D21 is a small tube thyratron, if anyone is wondering they're getting
singled out for attention.)


IIRC, Paul Pierce has one of the model of disk drive which was essentially the
RAMAC drive interfaced for use with the 7000 series.

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