On 1 Sep 2013 07:03:23 -0700, in bit.listserv.ibm-main you wrote: >On 9/1/2013 6:47 AM, Tom Russell wrote: >> In the case of multiple steps each allocating one file on the same >> tape, and no AFF parameter used, there was (is?) a significant >> difference between JES2 and JES3.
For allocating tape drives within a step (and UNIT=AFF is only within a step) UNIT=AFF is still needed to allocate SORTIN and SORTOUT in SORT operations to the same drive in both JES2 and JES3 (or for any other non-concurrent allocations where it is possible to share the drive. Clark Morris >> >> JES2 would allocate as many tapes as there were steps, and rewind an >> unload the volume after each step and issue a mount for the same >> volume on the next tape drive. JES3 had Tape High-Water Setup, and >> would allocate a single tape unit for the volume, and not rewind and >> unload it between steps. >> >> The only fix for JES2 was to add UNIT=AFF and DISP=(,PASS) to the >> JCL. JES3 didn't mind that you left them out. >> >> I can't test this as I have no JES3 system. > >Yes, It magically behaves almost as if JES3 under the covers issues an >MVS MOUNT command for the tape volume and then later issues the MVS >UNLOAD command at exactly the right time. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
