z/OS 1.12 provided a new parameter in parmlib member DEVSUPxx - NON_VSAM_XTIOT=YES/NO (where NO is the default). At that time, I wrote the following in my newsletter:
z/OS 1.12 - DEVSUPxx: Added NON_VSAM_XTIOT=YES/NO, where the default of NO leaves processing as it is currently. Specifying YES enables support for XTIOT, uncaptured UCB, and DSAB control blocks that reside above the 16 MB line for data sets using BSAM, QSAM, or BPAM. RECOMMENDATION: If you are storage-constrained below the 16 MB line, then specify YES on your test and development systems to see if any problems arise. Action will only be taken if the OPEN macro specifies these options. If you aren't storage-constrained, I would wait until there is more experience with this parameter. Has anybody turned this on in z/OS 1.12, and have you been able to measure any difference? In z/OS 1.13, JES, allocation, and DFSMS have added support to use XTIOT for subsystem data sets. Has anyone tried turning on the parameter in z/OS 1.13? I basically want to know whether it's safe to use. Thanks so much, Cheryl ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
