System programming information

Some bit definitions in the installation options control block (ADRUFO) permit DFSMSdss to communicate with the installation options exit routine. When the installation options exit does not want a function to be scheduled, it returns a code of 8. For the UIM to do this requires a bit definition of UFSTOP to be set in the ADRUFO. If a SYSIN or SYSPRINT data set is not to be allocated or all SYSIN/SYSPRINT is to be handled in storage, UFSYSIN and UFSYSPR specify this to DFSMSdss.

If the application allows DFSMSdss to handle SYSPRINT by not setting UFSYSPR, then the application can not write to SYSPRINT directly. The application can only insert SYSPRINT records at UIM exit points 2 or 10. If the application chooses to handle SYSPRINT by setting UFSYSPR, then the application is responsible for printing DFSMSdss messages from UIM exit points 2 or 10.

Three additional bits determine allowances within the UIM interaction: UFAIINV, UFUIMAL and UFUIMCH. Two additional bits indicate the existence or absence of an input restore/copydump data set or an output dump/copydump data set: UFNOIN and UFNOOUT respectively. Refer to z/OS DFSMS Installation Exits for more information about the installation options exit routine.

When DFSMSdss has been invoked by using the Application Interface and the UIM has been specified and is to be called, the following information is passed to the UIM on every exit call:

Register 1, which points to the interface parameter list pointer.
The interface parameter list pointer, which points to the DFSMSdss exit identification block. See ADREID0 data area for a detailed description of this block. This list consists of:
- A halfword field specifying the length of the remainder of the list.
- The remainder of the list that is mapped by the macro ADREID0. See Exit identification block below for the information contained in this block.

Upon return from the UIM, the user return code field is examined to determine the disposition of the current I/O record or data set (within the limits allowed to the exit).