58786 is the number of bytes available on the raw track. 56664 is what's left after the standard Record 0, which is present on every track of a volume formatted for z/OS use. I don't know about other OSes, and I don't recall seeing the 55996 figure before.
The old 3390 Reference Summary is available on bitsavers, and maybe some more complete documentation. sas On Wed, Nov 23, 2022 at 7:42 AM John Gateley <jrg.spur...@outlook.com> wrote: > Hello > > On all the disk volumes I have looked at, the format 4 DSCB field DS4DEVTK > (device track length) has the value 58786. > All the IBM documentation says that there are 56664 bytes in a track on a > 3390 drive. > At this link https://www.lascon.co.uk/hwd-3390-disks.php reference is > made to 55996 usable bytes out of 56664 per track. > > Is there some 'magic' formula that converts the value in DS4DEVTK to > either 56664 or 55996, or should I just ignore DS4DEVTK? > > Thanks > John > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
