On Tue, 2 May 2017 14:40:49 -0500, Steve Beaver wrote:
>
>How does GDG(+1) work outside JCL? (NO)
>
>Will each SVC 99 create a new generation? YES
>
Those two statements seem to contradict each other. The first says you can't
create
a new generation; the second says you can't. (Perhaps it can be done, but not
in
the DSN= key.)
>Can the programmer control this? DYNALLOC supports everything you can do in a
>DD Statement (It’s a lot of work but yes you can)
>
I know I've failed with BPXWDYN attempting to allocate two data sets (different
position on the same tape volume), but I do it readily in JCL.
VOL=REF? I suppose I could do an INFO to get the volser then use that
explicitly.
But see above.
In an IKJEFT01 step, how would I go about accessing a temp DSN passed from an
earlier step. Chasing control blocks? Yes, that's a lot of work.
My recent experience is with BPXWDYN. It's been decades since I used SVC 99
in assembler.
OK. Here's the list from SA23-1371-05 z/OS MVS Programming:
Authorized Assembler Services Guide iea3a812.pdf
JCL DD statement facilities not supported by dynamic allocation
Table 69 lists JCL DD statement facilities that cannot be used in dynamic
allocation.
Table 69. JCL DD Statement Facilities Not Supported by Dynamic Allocation
Restricted DDnames
Keyword Parameters
Positional Parameters
Selected Subparameters of Keywords
JOBCAT, STEPCAT, JOBLIB, and STEPLIB
CHKPT, DDNAME, DLM, and DSID
*, DATA, and DYNAM
Keyword Subparameter Not Supported
DCB reference to ddname of a previous step CYLOFL
NTM RKP
DISP PASS specification DSN reference to ddname (as in *.ddname)
ISAM area
name SPACE ABSTR specification
UNIT AFF
VOLUME
RETAIN specification REF=ddname
-- gil
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