Why MIM did not reply WAIT when all tape devices are in use in a particular system?

Products

• MIM Tape Sharing (MIA)
• MIM Resource Sharing (MIM)

Issue/Introduction

You had a situation where all tape devices were being used by applications. MIA TPCF was recovering well from tape allocations it could not satisfy, as witnessed by some MIM2046 messages...

MIM2046  TPCF     HAS REPLIED 'WAIT' TO THE ABOVE MESSAGE

However, an allocation for an important application failed and MIA didn't retry it. It seems that it detected all tape drives being OFFLINE, as seen by the bellow messages:

****

00:30:35.10 STC13983 00000285  MIM2042 jobname stepname ddname DEVICES OFFLINE 166        
                 166 00000285  ==> 22A0,22A1,22A2,22A3,22A4,22A5,22A6,22A7,22A8,22A9,22AA,22AB
                 < omitted range of tape devices >
                 166 00000285  ==> 243B,243C,243D,243E,243F                                  
00:30:35.12 STC13983 00000090 *153 MIM2060 jobname - REPLY DEVICE NAME OR 'CANCEL'.         

****

The tape device (VTS) addresses are shared among all systems in this particular Sysplex, but not ONLINE to this Sysplex.

Shouldn't MIM reply with WAIT when all tape drive addresses are in use in a particular system?

Resolution

This is normal behavior based on how TPCF responds to specific situations.

Looking at the documentation for the MIM TPCF Operating Values, where it describes the WAIT option for IEF238D (IEF238D=WAIT), there is a note that states that WAIT is usually not an option on the z/OS IEF238D message for jobs doing dynamic allocation. In this example, the jobname on the MIM2060 message was a started task.

This is a z/OS restriction not a MIA restriction. Typically started tasks do dynamic allocation for tape devices, whereas batch jobs use static allocation.