On Friday, 07/06/2007 at 11:17 AST, Rick Bourgeois <[EMAIL PROTECTED]> wrote: > But Alan, > > z/VM is supposed to provide virtualization so OS/390 shouldn't care what the > base hardware is.
That is a myth, Rick; one more commonly held that I would have believed just two years ago. You'll note that the hardware requirements for OS/390 and z/OS don't say "unless running on z/VM". z/VM virtualizes the underlying machine CPU architecture. That is, it takes whatever hardware you have and creates virtual machines with the same architecture. Some functions (aka "facilities") may be masked off or intercepted as needed to support (or not!) the virtual environment, but the instruction set and architecture are maintained. Add to that the virtualization of I/O, including simulation and selective virtualization. We do not, for example, surface multiple logical channel subsystems to a guest, even when the real I/O configuration includes them. All of the virtual devices appear within a single CSS. Alan Altmark z/VM Development IBM Endicott
