>I was just about to make some changes, and was "taking inventory" before >changing anything, when I noticed that the default system >built during the zVM 5.1 install has its paging and spooling packs using >cylinder zero for page / spool. Is this normal? I had >previously thought that cylinder zero should be PERM to keep anything from >being written on it. Will zVM honor the drive label, and >not page over it? Is there any advantage / disadvantage to this setup?
It is not a problem to have cylinder 0 allocated as PAGE or SPOL. z/VM will write page and spool data to cylinder 0 if it is allocated as such, but will not overwrite the records containing the volume information (label, allocation map, etc.). >Can I, without harm to foot, change cylinder zero to perm on the SPOL volume, >without disrupting the spool files stored on the >volume? Should I need to? Since page and spool information could have been written on cylinder 0, you should NOT change its allocation to PERM. But as mentioned above, there is no real need to change it since the volume information will not be overwritten. We've changed the allocation of cylinder 0 to PERM on the 3390 spool and page volumes in z/VM 5.2.0. John Franciscovich z/VM Development
