[inforoots] Mystery actuator

[John C Green Jr]

"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