MDS in JES3 handles some waiting, but that doesn't apply to JES2 and IAC the Initiator will still do the ENQ.
Be careful what you ask for; you might get it. A separate module to do the ENQ might not behave in a fashion that you like. -- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List <[email protected]> on behalf of Charles Mills <[email protected]> Sent: Thursday, July 5, 2018 6:35 PM To: [email protected] Subject: Re: REXX as JCL replacement Right. And I don't believe "JCL" does. I think think the scheduling component of JESx or something similar either waits or polls. Anyway, you are reading about SVC 99. I meant a separate module to do the ENQs. I would guess that SVC 99 does a RET=HAVE so there would be no harm in a pre-ENQ. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Paul Gilmartin Sent: Thursday, July 5, 2018 2:48 PM To: [email protected] Subject: Re: REXX as JCL replacement On Thu, 5 Jul 2018 13:29:01 -0700, Charles Mills wrote: >I have not really thought it through but I just cannot picture how building >some combination of Rexx or whatever + assembler one could not do 'n' >simultaneous ENQs. The facilities are there in MVS for the asking: > >"ENQ assigns control of one or more serially reusable resources to a task. If >any of >the resources are not available, the task might be placed in a wait condition >until >all of the requested resources are available." > From: z/OS IBM MVS Programming: Authorized Assembler Services Guide Version 2 Release 3 SA23-1371-30 Chapter 25. Dynamic allocation Requesting a data set that is in use: Rather than wait for another user to release a data set, volume, or device to obtain use of it, dynamic allocation fails a request by an unauthorized program. If an authorized program specifically requests a wait, dynamic allocation will wait. The designers were dedicated and capable. There's no way to wait for a dynamically allocated resource without introducing the hazard of a deadlock. -- gil ---------------------------------------------------------------------- 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 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
