BRODCAST with its 1 byte keys is probably the only data set using
non-unique hardware keys.
IIRC, the key values have the following meanings:
* (I think) header with pointers to the first system notice and the
first user directory blocks
* free (available) record
* system notice - operator SEND with SAVE
* user directory
* user mail - TSO SEND with SAVE
Decades ago I heard that SYSCTLG/CVOL and PDS directories both had 256
byte blocks with 8 byte keys because they used the same code for
processing. I have no idea whether that was true.
/Leonard
Seymour J Metz wrote on 5/13/2022 5:43 AM:
* BDAM
* ISAM
* PASSWORD
* PDS directory
* SYSCTLG/CVOL
* SYS1.BRODCAST
* VTOC
What about QTAM and TCAM message queues?
--
Shmuel (Seymour J.) Metz
http://mason.gmu.edu/~smetz3
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