folks ... I don't see anywhere in the programming guide where DIAG 250 does and does not work in terms of the whole disk. Clearly, the range of blocks to be worked in a single D250 call must be standard sizes (eg: all 4K or all 512 or some such). But does the disk itself have to be formatted entirely with blocks the same size? Can you still use DIAG 250 on a disk with 4K blocks in one area even though another area has a different blocksize?
Is there an impact to MDC from mixed blocksizes? I confess, this is a Linux question, and I will be asking on that list too. (Because I think there may be a driver issue within Linux.) For a lot of things, we need to use DIAG 250, especially for EDEV. But I've got a fresh installation of SLES10 and when I flag my 3390s for DIAG (supposedly meaning 250) they keep reverting back to DIAG disabled. These 3390s are CDL formatted, which means they have a z/OS label at the start which is *not* blocked at 4K like the rest of the disk. (I have not tried throwing "LDL" or all 4K disks at this Linux guest.) Thanks. -- R; <><
