On Friday, 11/14/2008 at 09:54 EST, "A. Harry Williams" <[EMAIL PROTECTED]> wrote: > Well technically, the VOL1 has a CCHHR to the VTOC. It doesn't have to be > on 0/0. See z/OS DFSMS: Using Data Sets SC27-7410 Appendix A. > > Something worthwhile understanding, and can be displayed easily with DDR. > (Hey, it's gotta be useful for something)
You're right, of course. In my attempt to define a CPVOL, I left out the actual standard. I meant that on a CPVOL, the VOL1 label *always* points you to 0/0/5, but that architecturally the VOL1 label can point anywhere. We saw this last week or the week before where someone posted that the VTOC was in the middle of the volume. That can happen only when the volume is formatted with ICKDSF INIT instead of ICKDSF CPVOL (as is done by CPFMTXA). For good reason since, in z/OS, you need to be able to move the VTOC around as it contains entries for the datasets resident thereon. With an unknown number of datasets, the size of the VTOC in unpredictable. With VM there are no datasets and no free space, so the VTOC can remain constant. (Can someone please bring me some water and a clean dust mask? All this digging and excavation is hot and thirsty work...) Alan Altmark z/VM Development IBM Endicott
