HP 3000 Manuals HP 3000 Manuals
Volume Set Format Change
by Ann Koehler
Commercial Systems Division
With this release of MPE XL, the format of the transaction management
(XM) log files has been changed to support enhancements to TurboIMAGE/XL.
The XM log files on the system volume set are converted to the new format
automatically when the system is updated to this release. The log files
on other volume sets are converted the first time the volume set is
mounted on an updated system. Again, this conversion is automatic.
During the conversion, status messages are displayed on the console that
indicate the progress of the conversion. The changes are not made
permanent until the following message is displayed:
XM log file migration completed successfully.
If an error or system abort occurs before this final message appears, all
changes will be rolled back and the modified volumes will be returned to
their original formats.
A volume set, in its converted state, must not be moved to a system
running an earlier version of MPE XL. The new XM log file format is not
compatible with the old format. A utility program is provided with this
release that returns the XM log files to their old format. It converts a
volume set back to the format expected by earlier releases of MPE XL. The
utility is invoked with the command:
RUN XMMIGBAK.PUB.SYS; INFO = "< volume_set_name>"
Specifying all will cause the program to loop through all currently
mounted volume sets, including the system volume set, and migrate each
volume set backward. If the system volume set is migrated then XMMIGBAK
will do a shutdown upon completion. Before attempting to migrate the
system volume set, user logging process should be shutdown.
Either SM (system manager) or OP (operator) capability is required to run
XMMIGBAK. The utility leaves the volume set closed. The volume set will
be converted back to the new format when it is opened again on a 3.0
system.
If a converted volume set is accidentally mounted on a 2. x version of
MPE XL, an error message is issued that indicates that the volume set and
the operating system are incompatible. The volume set will mount in the
unknown state. If the volume set is mounted on a version of MPE XL prior
to 2.0, it will mount without errors. However, file opens may fail
unpredictably and any attempt to write to the files on the volume set may
corrupt the files. To avoid problems, always run XMMIGBAK before moving
a volume set from a 3.0 system to any system running an earlier version
of MPE XL.