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The CA MIA GTAF facility determines what devices to manage based on the MIMINIT DEVCLASS and DEVLIST initialization parameters.
When a new I/O definition (IODF) is activated, which, in turn constructs a new EDT, it can define additional devices or remove existing devices from the systems and the control of CA MIA.
The CA MIA TPCF facility influences device selection during the z/OS allocation process. TPCF performs device preferencing based on user specified criteria enacted upon the list of devices eligible for a specific allocation request. z/OS creates this list of eligible devices (EDL) from the EDT.
Therefore, both facilities of CA MIA rely on the availability of the EDT and must detect and react appropriately to any change in the EDT.
To achieve this, CA MIA constantly evaluates the location of the current EDT by interrogating parameter lists at key CA MIA intercept points in the z/OS allocation process. In addition, CA MIA performs additional EDT verification as part of every control file cycle. When CA MIA detects a reconfiguration, it automatically resynchronizes in response.
CA MIA holds a bind or lock on the storage occupied by the EDT. Each control file cycle performed by CA MIA releases and re-achieves this bind. This process is also repeated as part of CA MIA processing in response to a z/OS ACTIVATE command or the CA MIA RESYNCH command.
It is normal for IOS Configuration displays to show CA MIA appearing to hold a continual bind on the EDT at all times. The bind that CA MIA maintains does not delay an ACTIVATE from completing.
As discussed in previously, during a dynamic configuration change, z/OS activates a new EDT definition.
CA MIA, like z/OS, processes all current and new allocation requests using the new primary EDT. Both z/OS and CA MIA use the secondary EDT to process allocation and allocation recovery requests issued before the dynamic configuration change completed. z/OS deletes the secondary EDT when the allocation requests, issued before the dynamic configuration, complete.
The following is an example of a D IOS,CONFIG(EDT) display showing binds on both the primary and secondary EDT:
D IOS,CONFIG(EDT) IOS506I 11.56.09 I/O CONFIG DATA 514 ELIGIBLE DEVICE TABLE LATCH COUNTS 1 OUTSTANDING BINDS ON PRIMARY EDT ASID = 0023 JOBNAME = MIMGR 1 OUTSTANDING BINDS ON SECONDARY EDT ASID = 0028 JOBNAME=TAPE1
In this CA MIA address space example, MIMGR holds a bind on the primary EDT. Job name TAPE1, which started before the ACTIVATE initiated, went into recovery and has not yet completed.
TAPE1 holds a bind on the secondary EDT, which was the primary EDT when this job went through allocation. As soon as TAPE1 completes, the secondary EDT is deleted and an IOS501I ACTIVATE CLEANUP COMPLETE is issued.
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