Do I understand correctly? You want to submit the same JCL you are currently submitting. By fiddling with the library containing utility A (or possibility a library earlier in some concatenation), the step that originally executed A will now execute your program. Your program will change the allocation for a known DD statement and then execute utility B.
There are tools that will give you the DSN specified on a DD statement. Unless the DD statement in question specifies DEFER, the tape mount will be requested and need to be satisfied prior to your program getting control. I don't know if it matters to the various allocation tools whether the tape has been mounted or not when you invoke those tools. If the tape has been mounted, you may need to cause a dismount. I don't know if the dismount command can unload a tape mounted by JCL (technically I guess it was mounted by the initiator). If not, you may need to open the DCB and then close it specifying FREE. Once the tape is not mounted, you should be able to free the DD name. Once you have the DSN and the DD name is no longer allocated, you should be able to uncatalog the DSN, allocate the DD name with the DSN and the desired disposition, and execute utility B. > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[email protected]] On > Behalf Of PINION, RICHARD W. > Sent: Thursday, October 19, 2017 12:55 PM > To: [email protected] > Subject: Re: Data set allocation from JCL and REXX/CLIST > > John your last assumption is correct. What I'm attempting to do is this. We > have utility A, > which I want to replace with utility B without making hundreds of JCL > changes, and going > through change control. > > I have an assembler program which invokes CLIST/REXX. I'll rename my > assembler > program to the name of utility A. My program will invoke my CLIST/REXX, > which will > parse the SYSIN statements that went into utility A, and create the > appropriate statements > for utility B. Utility A used a tape as output. Utility B will use that > name as its control file > name, and perform its version of what utility A did, with its own output > going to another > tape data set name. > > -----Original Message----- > > >On Thu, Oct 19, 2017 at 1:27 PM, PINION, RICHARD W. wrote: > > > > > >> I think I know that the answer is "no", but I'll ask anyway in case > > >> it is possible. I have a NEW,CATLG data set that is allocated to > > >> tape via JCL. I have a REXX/CLIST that is running in the step that > > >> has the tape data set. I would like to FREE that data set from the > > >> REXX/CLIST and then allocate a NEW CATALOG of the same data set > > >> name to DASD from the REXX/CLIST. Aside from using SMS to redirect > > >> the allocation to DASD is this possible? > > >> FIRST TENNESSEE > > >> ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
