Element or feature: | TSO/E |
When change was introduced: | z/OS V2R1. |
Applies to migration from: | z/OS V1R13 and z/OS V1R12. |
Timing: | Before installing z/OS V2R1. |
Is the migration action required? | Yes, if you depend upon the behavior that occurred before z/OS V2R1. |
Target system hardware requirements: | None. |
Target system software requirements: | None. |
Other system (coexistence or fallback) requirements: | None. |
Restrictions: | None. |
System impacts: | None. |
Related IBM Health Checker for z/OS check: | None. |
Steps to take: This item is intended to alert users of EXECIO to a behavioral change that may occur due to a relaxing the restriction on null data sets within a concatenation being read by EXECIO DISKR or DISKRU. If your exec tests the EXECIO return code and handles RC=4, you will likely have no action that needs to be taken. The RC=4 that was previously returned when EXECIO detected a null data set within the DD concatenation being read by EXECIO is still a possible return code, if the concatenation contains a null data set which is not SMS managed. Yet, if the EXECIO read against a DD containing a null data set completes successfully (i.e. RC=0 or 2), you would typically have no exceptional action to take, since the read operation will have worked as if the empty data set were not even present.
On the other hand, if you have an exec that expects EXECIO to fail whenever it reads a concatenation containing a null data set, and you exec depends on this EXECIO read failure, you should now look for RC=0 or RC=2 to allow for the possibility of success.
Reference information: For details about EXECIO see, z/OS TSO/E REXX Reference. For details about messages IRX0670E and IRX0566E, see z/OS TSO/E Messages.