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Author question about dynalloc
jim

2006-05-19, 6:57 pm

I have done a dynalloc of a SHR dsn. I have verified that the dsn was
allocated to my TSO session. I did the same thing with the same dsn
via use of a DD in the batch jcl I was running. In both cases, I
looked at the JFCB. They are different. Why?

John W. Kennedy

2006-05-19, 6:57 pm

jim wrote:
> I have done a dynalloc of a SHR dsn. I have verified that the dsn was
> allocated to my TSO session. I did the same thing with the same dsn
> via use of a DD in the batch jcl I was running. In both cases, I
> looked at the JFCB. They are different. Why?


The only sane answer to this question, as posed, is that they are
different because they are not the same.

--
John W. Kennedy
"The blind rulers of Logres
Nourished the land on a fallacy of rational virtue."
-- Charles Williams. "Taliessin through Logres: Prelude"
Steve Myers

2006-05-20, 9:57 pm

What fields did not compare equal?

I just tried it, and all fields compared equal.

jim wrote:
> I have done a dynalloc of a SHR dsn. I have verified that the dsn was
> allocated to my TSO session. I did the same thing with the same dsn
> via use of a DD in the batch jcl I was running. In both cases, I
> looked at the JFCB. They are different. Why?
>

Steve Myers

2006-05-21, 3:56 am

I have to take back my first comment. After I updated the DYNALLOC
request to not use an existing allocation, field JFCBEXAD did not
compare equal. This is something I would expect not to compare equal.

JFCBEXAD DS CL3 - SYSTEM VIRTUAL ADDRESS (SVA) OF FIRST JFCB
* EXTENSION BLOCK
* JFCBX (IEFJFCBX) - contains additional vols
* JFCBE (IEFJFCBE) - contains 3800 printer info
* (MDC303) @Z40MP9A

DP DC A(X'80000000'+RB)
RB DC 0A(0),AL1(S99RBEND-S99RB,S99VRBAL,S99NOCNV,0)
DC 2AL2(0)
DC A(TXTPP)
DC 2A(0)
TXTPP DC A(TXT01,TXT02,X'80000000'+TXT03)
TXT01 DC AL2(DALDSNAM,1,L'DSN)
DSN DC C'SYS1.MACLIB'
TXT02 DC AL2(DALRTDDN,1,L'ADDN)
ADDN DC CL8' '
TXT03 DC AL2(DALSTATS,1,1),AL1(X'08')


jim wrote:
> I have done a dynalloc of a SHR dsn. I have verified that the dsn was
> allocated to my TSO session. I did the same thing with the same dsn
> via use of a DD in the batch jcl I was running. In both cases, I
> looked at the JFCB. They are different. Why?
>

Barry Schwarz

2006-05-21, 7:57 am

On 19 May 2006 11:23:04 -0700, "jim" <jwalker216@yahoo.com> wrote:

>I have done a dynalloc of a SHR dsn. I have verified that the dsn was
>allocated to my TSO session. I did the same thing with the same dsn
>via use of a DD in the batch jcl I was running. In both cases, I
>looked at the JFCB. They are different. Why?


How did you verify the dsn was allocated? How did you look at the
JFCB in each case? Which JFCB fields were different? At what point
in the two cases did you look at the JFCB?


Remove del for email
jim

2006-05-22, 6:58 pm

I checked the field in expediter. Later I did a snap of the field.

jim

2006-05-22, 6:58 pm

I verified via the use of a ?homegrown clist called ISRDDN. It showed
the proper ddname along with the proper dsn as being allocated to my
TSO session.

Steve Myers

2006-05-22, 6:58 pm

What field? A JFCB consists of many different fields. Which field did
you find that did not compare equal? It is immaterial if the entire
JFCB did not compare equal - that WILL NOT HAPPEN.

jim wrote:
> I checked the field in expediter. Later I did a snap of the field.
>

jim

2006-05-23, 6:57 pm

I don't know what field it was. No, I don't know what mapping macro to
use.

Steve Myers

2006-05-24, 3:57 am

Jim - you've got to learn about the control blocks, how they are mapped,
and where the mapping macros for them are found. Where did you find out
about JFCB?

In any event, z/OS consists of 2 BIG subcomponents: MVS and DFSMS. It's
not always clear who owns what. The manuals for each of these
components are found in
http://publibz.boulder.ibm.com/cgi-...helves/IEA2BK61
for MVS, and
http://publibz.boulder.ibm.com/cgi-...helves/DGT2BK51
for DFSMS

In the MVS set, there are 5 manuals clearly labeled "Data Areas." One
of them covers data areas IVT-RCWK. This is where to see if the JDFCB
is discussed, since J is higher in the collating sequence than I.

The mapping macros are usually in SYS1.MACLIB or SYS1.MODGEN.
Colin Campbell

2006-05-24, 6:57 pm

jim wrote:
> I don't know what field it was. No, I don't know what mapping macro to
> use.
>
>

I'm speaking from memory, but I believe it is IEFJFCBN, probably in the
SYS1.MODGEN or SYS1.AMODGEN macro library.
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