On IBM internal systems, they break the 6 char volser into 3 2 character fields. The first 2 characters are for the volume usage (PG for paging, SP for spool, RS for sysres, you get the idea). The next 2 identify the LPAR or VM system (so you need a list somewhere that maps these 2 character ids to your LPARs). The last 2 are the "serial number", which can be any unique combination of letters and numbers.
Of course, you can use 1 character for system id and volume type as Mike suggested, and have more characters available for the serial number. -- Bruce Hayden z/VM and Linux on System z ATS IBM, Endicott, NY
