IBM photostore (was: Re: digital camera capabilities)

Chris Kennedy chris at
Wed Dec 19 01:19:28 CST 2007

Roy J. Tellason wrote:
> On Tuesday 18 December 2007 23:39, Chuck Guzis wrote:
>> Ever hear of the IBM 1360 photostore?


>> It was used a verb at Lawrence Livermore--as in "Your file has been
>> photostored."  A very unfortunate happening...
> Unfortunate as in it wasn't directly accessible then?  I thought that the 
> point of such a setup was to keep a file accessible in digital form.  Or is 
> that some sort of offline storage,  like punched cards?

One of these was in use at LBL as well, where it was sometimes called
chipstore (an apparent reference to the individual pieces of film).
Chips were organized into cells, cells into trays.  When a particular
chip was needed the appropriate tray was rotated into place, an arm
selected the appropriate cell and it was sucked out of the tray and sent
on Mr. Toad's Pneumatic Wild Ride to the reading station, where the cell
was popped open and the film loaded into the reader.

That was the theory, at least.  Unfortunately it had a very bad habit of
sometimes screwing up the last step; consequently there was frequently a
broom nearby in the company of a small pile of chips.

I recall that data density was quite high, reading speed was high but
access times were long.  Writing used some combination of electron beam
and wet chemistry, so while the bit rate was respectable the throughput
was -er- on the slow side.  IIRC the primary use was to store census data.

Co-located in the same room with the chipstore was a truly strange
magnetic storage device from IBM that was referred to as MSS.  It
consisted of a carousel of rectangular magnetic sheets and a single
reader-writer station; the carousel would rotate the correct sheet into
the station and then the sheet would move up and down past a series of
fixed heads.

What made all of this truly strange is that these IBM peripherals hung
off CDC channel controllers that interfaced them to 6000 series
machines.  CDC and IBM FEs would periodically get into pissing contests
over who was responsible for various faults; recurring ones would end up
with a piece of paper taped to the channel controller that would say
something to the effect of "TP XYZ +X volts -> IBM problem, -Y volts ->
CDC problem".

Chris Kennedy
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"Mr. McKittrick, after careful consideration..."

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