CDC 9429 Floppy maintenance manual

Chuck Guzis cclist at
Sun May 8 15:49:49 CDT 2016

On 05/08/2016 01:30 PM, tony duell wrote:

> They are considerably better than the Shugart drives with the plastic
> disk with a spiral groove for the head positioner....

Ah yes, the SA-400.  When I was evaluating one, I wondered if Shugart
was really serious about the things.  Doubtless some engineer at Shugart
was quite proud of himself for designing a ball-bearing follower for the
spiral groove.  Marks for being cheap.

Oddly, my own troubles with the SA-400 (believe it or not, this was used
as the original IBM offering for the 5150 drive) were with the tach
circuit.  Mine blew a small inductor.

Among all of the 5.25" FH drives offered at the time, my vote still goes
to Micropolis for designing the Sherman tank of drives.  Leadscrew
positioner with multiple steps per track.  Probably among the most
expensive 5.25" drives also.

To their credit, Shugart did have the best hub-clamp setup.


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