Anybody has Control Data (CDC) disk packs for 841 and 844 disk drives to spare with?

Paul Koning paulkoning at
Mon Jun 5 09:48:03 CDT 2017

> On Jun 5, 2017, at 10:33 AM, P Gebhardt via cctalk <cctalk at> wrote:
>> ...
>> The platters can be replaced with ones from the single-platter IBM 2315 (ie. RK05) and use similar head technology which is pretty rugged.
> Yes, I kept the disk packs. However, I guess that one need to have special alignment tools to replace single platters of a disk pack. Or is a reformat enough, as long as the servo disk surface is error-free and available?

Not all disks have servo on disk.  1311 if I remember right simply has detents in the head actuator to define the track positions.  RK05 has a servo system in the actuator, but nothing on the pack.

If you have that kind of pack, replacing the platter centered accurately enough that you don't get excessive vibration, then reformatting, should be all you need.


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