While best practice is to let the system choose, if you insist on using VOL=SER=foo for a temporary, it will work. IMHO, it's best to let SMS do its thing.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 עַם יִשְׂרָאֵל חַי ________________________________________ From: IBM Mainframe Discussion List <[email protected]> on behalf of Jon Perryman <[email protected]> Sent: Thursday, November 23, 2023 1:53 PM To: [email protected] Subject: Re: UNIX REXX LINKMVS TASKLIB? On Thu, 23 Nov 2023 01:47:18 -0600, Paul Gilmartin <[email protected]> wrote: >>On Thu, 23 Nov 2023 04:18:05 +0000, Farley, Peter wrote: >>In this day and age, why in the world would you evec contemplate using a >>non-cataloged library? >> >In parallel with the JCL Ref. mentioning use of temporary data sets as link >libraries: ><https://www.ibm.com/docs/en/zos/3.1.0?topic=statement-pgm-parameter> > Use the PGM parameter ..., or a temporary library. Temporary datasets never use VOL=SER=. They are accessed through a DD that optionally exists for the life of the job (DDNAME= or DSN=&&XXX). Technically they are uncatalogued but the word uncatalogued implies use of VOL=SER=, >>Performance was admirable and acceptable but this usage was obviously not a >>high-volume commercial application, so YMMV. >> >I was just taking to heart the advice in ><https://www.ibm.com/docs/en/zos/3.1.0?topic=shell-controlling-use-steplibs> > ... To improve performance of the z/OS® shell, avoid propagating STEPLIBs > ... Think of this in terms of z/OS. USS STEPLIB variable is actually an attach tasklib (not a true step). The problem occurs when you FORK() a process which must allocate a new unique DDN, open it and read the directories during ATTACH. Much of UNIX is built around FORKing is cheap. For instance consider MAKE (compile) which could potentially do a 100,000 FORKs in a short amount of time. Performance is in the eye of the beholder. Performance is more than one thing that runs extremely fast. z/OS can run at 100% busy without impacting users. If I run MAKE to compile in LINUX, it is treated the same as if I'm using edit. Performance must be measured in overall impact which can vary greatly by environment. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
