Re: Where did CKD disks come from?

On 12/12/2024 11:55 PM, Lynn Wheeler wrote:

John Levine <johnl@taugh.com> writes:

Any idea who invented CKD?  The Pugh et al history book says a lot about
disk hardware but nothing about software or CKD.  Someone must have invented
it but who?  When?

 not who but why:
https://retrocomputing.stackexchange.com/questions/24074/how-did-reserve-tracks-work-on-early-hard-disks
Count Key Data was IBM's answer to unify three very different methods of
data storage (Disk, Drum, Cells) into a single interface, while at the
same time offloading basic tasks to hardware.
 discussion "spare tracks" & "standard configuration"
https://archive.computerhistory.org/resources/access/text/2014/07/102739924-05-03-acc.pdf
Jack: That was the first time in a sense that you had an index, which is now
standard configuration.
Al: Right.
Jack: Standard configuration. The other thing that we did, that we
subsequently cursed a lot, was the idea of variable record length and count
key data as the format. I don't know if IBM's gotten rid of that yet.
 ... seems to imply collective "we" team/group
 and more discussion of 1301&1311 to CKD 2311 (disk)
https://archive.computerhistory.org/resources/text/Oral_History/IBM_1311_2311/IBM_1311_2311.oral_history.2005.102657931.pdf
 

For some damn reason this makes me think of fuzzy bits on a disk. I am not sure why!
http://dmweb.free.fr/community/documentation/copy-protection/copy-protection/
http://dmweb.free.fr/community/documentation/copy-protection/copy-protection-apple-iigs/