Hello, VM experts,
I'm preparing myself for teaching the mysteries of VSE and VM systems
work and I'm reminded that when one prepares to teach something one
discovers many holes and uncertainties in one's own knowledge. Today
I thought I'd educate myself about IPL bootstrap records in case one
of my students asks about them. My theory, which I wanted to test,
was that they're written by ICKDSF whenever an INIT is done (for MVS
and VSE volumes) or a CPVOL FORMAT is done (for VM volumes). Based
on what I've seen today, this seems to be true.
But while looking around our system I discovered a volume that had
originally been created for VSE use as a full-pack minidisk. In
other words, it had been prepared using ICKDSF INIT (which would have
created a vtoc). However, somewhere along the way it was decided
that this volume would have several minidisks on it. In other words,
it was no longer to be a full-pack minidisk. CPVOL FORMAT was never
used on this volume, so cylinder 0 was left unchanged, with no
allocation information. (If it were to have allocation information,
it would have been PERM for the whole volume.) My initial reaction
was surprise, but then I figured that possibly CP can tolerate a
volume without allocation information as long as its sole use is
PERM. It sure seems to be true that such a volume needs only a VOL1
label to make CP happy.
My question is this: is there any reason to be concerned about such
a volume not having an allocation map?
- Tom
P.S. The IPL bootstrap records are different between VSE and VM, but
since we're not IPLing using this volume, that isn't an issue.
Tom Cluster
County of Sonoma
Santa Rosa, CA
(707) 565-3384 (Tuesdays and Wednesdays only)
