> I was able to successfully do this with a volume that was DEDICATED to a > LINUX GUEST.. > but not this MDISK situation.
The DEDICATEd mode gave both Linux and MVS access to cylinder zero. The minidisk you allocated just now gave Linux access to cylinder one, so it no longer accesses cylinder zero. Linux and MVS now see two different things. > I'm a VM newbie...so I guess I know I'm doing something wrong here... You can have a "minidisk" that starts at cyl 0. That's fine. In such a case, you have to trust that the guest scribbling on that volume will not clobber the IBM label, because VM will need it to reference that disk in the future (unless you ref by I/O addr). Obviously, since you're using CDL for shared access with MVS, you want to preserve the IBM label for MVS' sake too! And CDL does that. In cases where you DO NOT have CDL (like older Linux/390) you would have to off-set the start of the minidisk from cyl zero to some other place. If you clobber the IBM label, VM and MVS can both get confused. (MVS gets worse heartburn over it.) -- RMT
