Three IBMers - representatives from the JES2 development and support camps - took technical questions from the audience.

I asked how I could pass data between exit #15 calls. Exit #15 gets called twice, once for selection and once for actual dataset printing. I was stashing my data in PDBFLSHC, the FLASH count parameter from JCL. I knew this was reprehensible, but what could I do - there is no user data area in the PDDB. IBM sez: use a PCE or DCT user field; PRPU single-threads between the selection and print calls to exit #15 (this makes me a happy puppy.)

Someone asked if IBM would consider enhancing the $DA command in JES2 2.2.0 in the same way that they enhanced it in JES2 3.1.1. IBM replied in essence: "Fat chance. The $SCAN service was involved in the enhancement too, and that's too big a change to retrofit."

Several questions arose regarding when spin datasets are actually deallocated from the SPOOL. Here is the scoop: spin datasets are deleted from the SPOOL when they are printed, UNLESS:

• multiple destinations were specified (via a "/*OUTPUT" card, or more than one "// OUTPUT DD" statement was referred to.
• the dataset was spun via override disposition (SVC 99)

I asked if there was any documentation on the external writer interface. There is none, but I was pointed to a presentation done by Andrew Schmidt a couple of SHAREs ago on the JES3-PSO interface.