VME Support

Additional Software Incident reporting from MAMPHY at OVME7.

The MAMPHY enhancement to provide FLF space register cell checksum checking has the potential to report Software Incidents specifying failure code -35023 and incorporating the following new message in the ‘Extra Info’ section:

INCIDENT ON PARTITION xxxxxx, CHECKSUM FAILURE ON FLF SPACE
REGISTER CELL WITH UNIT_FLAG_LIST_BASE OF HEX nnnnnnnn

with the additional text on the 7th incident per partition establishment:

NO MORE SUCH INCIDENTS WILL BE LOGGED FOR THIS PARTITION UNTIL IT IS RE-ESTABLISHED.

This message is only reported when an FLF space register cell has been read in for the partition with name xxxxxx and an anomaly has been noted in that the newly computed checksum for its bit map allocation does not correspond with its embedded checksum.

The cell may be identified from the unit flag list base, the first space register cell will have a value of zero and this is incremented by Hex 380 for each cell in the chain. A space register cell contains the unit flag list base in bytes 12 to 15 inclusive of the cell.

Should there be more than one occurrence of this problem whilst a partition is established for use then only the first such incident will appear in the Operator’s software incident picture and up to 7 occurrences will be registered in the system journal per establishment. Should the number of incidents exceed 7 then reporting will be suspended and will not resume until either the partition is re-established or the time reaches midnight. The count of incidents on established partitions is reset to zero at midnight providing that this is not prevented by their usage.

Multiple copies for the same cell may appear.

The first occurrence of such an FLF problem whilst a partition is established (and again following midnight if appropriate) will also be notified as a System Prompt to the operator:

MM S/W INCIDENT, SEE SI OPF

• Press 'send' to acknowledge receipt of the prompt which will clear it from the screen.
• Take action to rectify the fault as soon as possible.

Recovery from FLF space register cell checksum failures:
In order to overcome a reported FLF space register cell checksum failure, the operations staff must follow the recommended actions for running TIDY_PARTITION_FREE_SPACE on the relevant partition as described in section E1 of BN51140 OpenVME: Using and Managing Disc Systems for OVME7 and reiterated for convenience in the section below:

Recommended actions for running TIDY_PARTITION_FREE_SPACE:

• Gain exclusive access to the partition in question.
• Take a security copy of the partition.
• If the partition is currently a multiplexed partition then use CHANGE_PARTITION_PLEX_DETAILS to reduce the number of active plexes to 1 by marking additional plexes as BROKEN.
• Run TIDY_PARTITION_FREE_SPACE on the remaining single plex to ensure a consistent image of the partition is analysed to assess the space allocation and reset the details in the cell.
• If the partition is a multiplexed partition then the additional plexes should be restored as required using RESTORE_PARTITION_PLEX.
• Once the partition has been successfully reinstated and is in use with no further problems reported, the security copy (with the FLF checksum problem) may be deleted.