I think you're confusing him. He was asking about GRS. There are 3 differ ent ways to share DASD R/W in MVS:
1. Reserve/Release 2. GRS ring 3. A parallel sysplex If all your MVS (z/OS) systems are guests of one z/VM system, then VM pro vides 1. Virtual Reserve/Release 2. Virtual CTCs 3. Virtual Parallel Sysplex Real & Virtual Reserve/Release share the performance problem that loc king is at the full pack level. A GRS ring performs better, and parallel sysplex performs even be tter. You didn't say you wanted to share with a non-guest z/OS system. If you w ant to do that: 1. You can have both real and virtual reserve/release 2. I don't know if a GRS ring can include guests with real z/OS systems o r not. 3. A virtual sysplex CANNOT be extended to real z/OS system or to a real parallel sysplex. I'd almost forgotten about GRS, as we have gone entirely to parallel sysp lex. I don't know if it can support all those different releases of z/OS or not. I don't even know if GRS is still supported at all. Alan Ackerman Alan (dot) Ackerman (at) Bank of America (dot) com
