What happens when DISP=MOD is used in ENDEVOR Processors?

Document ID : KB000048159
Last Modified Date : 14/02/2018
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Description:

When using "DISP=MOD" in processor the dataset can be allocated in an unexpected way,for example the Dataset is allocated to a non-SMS managed disk instead of a SMS managed as a temporary dataset should be.

Solution:

Here is an explanation of what is happening with DISP=MOD:

  • For each processor step, ENDEVOR dynamically allocates the specified datasets by means of the DYNALLOC macro provided by MVS (also known as SVC 99).

  • Unlike JCL allocation, the DYNALLOC macro does not support the allocation of a temporary dataset with DISP=MOD.

  • ENDEVOR needs therefore to simulate it by allocating a permanent (cataloged) dataset and deleting it afterwards.

  • Trying to catalog a dataset with a temporary dataset name may lead to various problems.

You can prevent these problems by either:

  • Avoiding to use DISP=MOD for temporary datasets in processors.

  • Using the C1DEFLTS MODHLI= parameter which causes ENDEVOR to format the dataset name differently for temporary datasets with DISP=MOD, therefore preventing this symptom.

Note that the MODHLI value will be the first qualifier for the dataset name, so you need to ensure it will be valid for cataloged datasets at your site.

If one want to implement MODHLI, please check the option DS_INTERNAL_TEMP from ENCOPTBL.