APAR OA34311 enhances z/OS V1R12 to allow a dispatchable unit
(maybe only task?) running in subspace mode to access virtual
storage above the 2GB bar.
This enhancement was not provided for z/OS V1R11.
Our software needs to run on z/OS V1R11, and it sometimes
needs to run in subspace mode.
We would like to be able to determine programmatically whether
our task is in subspace mode, so as to bring data below the bar
for it. We have tried to use the STCBSST (X'10') bit of the STCBFLG1
byte at 25 off the STCB. There seem to be situations in which the
task is in subspace mode, but the bit is not set.
I wrote a test program which performed the following steps (sorry
this is so complicated, but i have developed infrastructure and it's
easier to just plug into it than to rewrite it):
1. JES2 starts the job-step in key 8. The test code then does:
2. MODESET KEY=ZERO
3. Set TCBPKF to X'60'
4. Allocate some storage in key 6. Copy parameters so the
module i'm going to launch will be able to access them.
5. ATTACH a JOBSTEP task. It ends up running in key 6,
PROBLEM state. This task then does:
6. ATTACH a non-JOBSTEP task, which does:
7a. IARSUBSP IDENTIFY
7b. IARSUBSP CREATE
7c. IARSUBSP ASSIGN
8. ALESERV ADD,STOKEN=token,ALET=alet
where the token is as returned by step 7b.
9. BSG (BRANCH IN SUBSPACE GROUP)
10. Invoke XDC via its SVC HOOK.
I then examine the STCBFLG1 byte and find that it's zero.
If the program continues and attempts to access storage
above the bar (you could insert a step between 6 and 7
to obtain this storage), i get S0C4-3B, as documented
in OA34311 (i'm running on z/OS V1R11. There is no
problem on z/OS V1R12, as we have applied the PTF).
Are there some other pieces of data i should be examin-
ing to see whether the current task has subspaces?
Am i having this problem only because the task which
is creating the subspace is not JOBSTEP?
Thank you for any help,
Justin R. Bendich
jbendich <at> austin <dot> rr <dot> com
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