On Sat, 25 Dec 2021 at 18:57, Bob Polmanter <wably@...> wrote:
[...]
I always run VS1 in a virtual machine, and I have TK4 MVS in a virtual
machine as well right along side of it. That way, I can use TSO on MVS to
edit the parmlib members or proclibs members of the VS1 volumes without
having to do everything in batch. MVS and VS1 can share the VS1 dasd in
R/W mode, if you define them correctly in the CP directory, using MDISK
statements with MWV. The V in MWV is the critical specification - it
forces CP to ensure data integrity between the guest OS'es using virtual
reserve/release.
Have to be careful with this... Support for reserve/release on the
virtualized hardware doesn't mean that MVS or VS1 will issue them. The
devices have to be gen'd shared in the guests as well. And even then, the
integrity is only for VTOC updates - there is no general protection against
updating a dataset from both systems at the same time. For that you need
some scheme to propagate ENQs across systems - something IBM didn't provide
until much later with GRS via CTCs. There were some third party products
that did, but presumably we don't have access to those.
Tony H.
