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Advanced Topics › How You Influence Device Selection › Limiting Access to Devices Through the OVERGENNED Status

Limiting Access to Devices Through the OVERGENNED Status

The SETOPTION TPCF OVGINELIG={NO|YES|JOBRESV} setting determines whether OVERGENNED devices are marked ineligible in the EDL. Marking OVERGENNED devices as ineligible in the EDL eliminates them from allocation early in the allocation process and affects the way device selection is performed for a job. Marking OVERGENNED devices ineligible in the EDL can prevent jobs from going into allocation recovery and prevent jobs from being canceled in allocation recovery.

Here are some examples of using SETOPTION TPCF OVGINELIG. In all the following examples, TAPE1 has an EDL consisting of devices 580-58F.

Examples:

  1. This example assumes the following are true:

    When TAPE1 goes into allocation, devices 580-586 are eliminated because they are reserved for another job. Since devices 587-58F are OVG, they are offline. TAPE1 goes into allocation recovery with an offline device list of 587-58F. CA MIA eliminates 587-58F from the offline device list because they are OVG. There are no devices left eligible for allocation and the job is canceled in allocation recovery by TPCF after the message MIM2044 ALL DEVICES HAVE BEEN ELIMINATED is issued.

  2. This example assumes the same values as the proceeding example, except SET TPCF OVGINELIG=YES

    This time, when TAPE1 goes into allocation, devices 580-586 are eliminated because they are reserved for another job and devices 587-58F are eliminated because they are OVG and OVGINELIG=YES. CA MIA has eliminated all devices during the initial allocation process so CA MIA restores 580-586 to the job for use. If a device is available in the 580-586 range, then the job allocates the device. If not, then the job goes into allocation recovery with 580-586 in the offline device list or wait eligible list. In the previous example, this job was canceled. In this example, the job is not canceled but is allowed to use a device reserved for another job.

    In this case, SET TPCF OVGINELIG=JOBRESV would have the same effect as SET TPCF OVGINELIG=YES since job reserve is in effect.

  3. This example assumes the following are true:

    When TAPE1 goes into allocation, all devices are offline because they are OVG. TAPE1 goes into allocation recovery with an offline device list of 580-58F. CA MIA eliminates 580-58F because they are OVG. There are no devices eligible for this allocation. TPCF cancels the job in allocation recovery after the MIM2044 message is issued.

  4. This example assumes the same values as the preceding example, except SET TPCF OVGINELIG=YES

    When TAPE1 goes into allocation, all devices are eliminated because OVGINELIG=YES. The job ends with a START COMMAND DEVICE ALLOCATION ERROR from the operating system.

    In examples 3 and 4 the job ends. In example 3, however, TAPE1 had to go through the entire allocation recovery process before being canceled. In example 4, TAPE1 ended before entering allocation recovery, eliminating the unnecessary overhead of allocation recovery.

    If SET TPCF OVGINELIG=JOBRESV was specified, then the effect would be the same as example 3, since no job reserve is in effect.