Another mystery head quiz

On 04/18/2015 04:44 PM, Chuck Guzis wrote: Okay, nobody venturing a guess after a week... This is one of the heads from a CDC 808 disk drive slider. Note the 6 channels. I say that I'm "pretty certain" because this may also be a head from the ill-fated 821 disk drive, sort of a "super 808", with more storage. I don't think the 821 ever made it into the wild, as it was shortly dumped in favor of the 844 "pack" drive that many know so well. Since the CEs were trashing all sorts of equipment at the time I grabbed this, it's hard to say. 72 disk platters, two spindle motors, hydraulic positioners, water cooling and somewhere around 6 ft. tall. I can't find a photo on the web, but I suspect there's one there. Usually referred to generically as a "6638" or "6639" type drive, which was really the name of the controller, not the drive itself. A brief overview of it can be found on Bitsavers: http://www.bitsavers.org/pdf/cdc/cyber/peripheralCtlr/602500800A_6638_Disk_… --Chuck