[inforoots] Mystery actuator

[Utleyb at aol.com]

In a message dated 3/1/2006 3:34:15 AM Central Standard Time,  
jcgreen00 at comcast.net writes:

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"Peter Capek"  <capek at ieee.org> wrote:

>It's certainly a disk  actuator.   The 2 white disks (which look to
>be about an inch  in diameter, but with a slice taken off each side)
>visible in the  ..1939.. photo look like the read/write heads, so
>apparently two per  disk, moving on one access arm.
>
>Just judging from the scale of  this and estimating the size, I
>would guess this assembly is from a  large disk - perhaps 24 inches,
>maybe more, in diameter (and hence,  likely, no newer than about
>1970).
>
>The arms appear to be  numbered up to 10 in the 1940 photo, so there
>were probably 20 surfaces  used in the drive.
>
>Peter Capek

Definitely a disk  read/write assembly.  Linear induction motor
patented by Peripheral  Equipment Corp (later Memorex) and first used
on their 630 drive first  shipped in 1967 which provides a lower
bound for the vintage.  630 was  first OEM plug compatible with IBM
2311.

Couldn't be 24 inch drive  as they died long before 1967.  Head
size is consistent with 2311 and  2314.  20 heads makes it a 2314
compatible drive.  Two heads per  surface was obviously for speed as
arm only had to move 1" rather than 2"  to reach all cylinders.  Given
it's from a Univac shop I'd say your  best bet is an ISS 2314 compatible
drive.  ISS was bought by TELEX  which later sold it to Sperry Rand
which sold it to CDC before merging with  Burroughs to become Unisys.

Memorex was shipping 660 (IBM 2314  compatible) that worked by SEP1969.
ISS wouldn't have been far  behind.

Ask Jim Porter or check out his website:   http://www.disktrend.com/
for possible positive identification of the  device.

Regards,
John  Green

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The number of platters is right for a 2314 but too many for a 2311.
 
Brian Utley
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