>From Info APAR II08285:
NOTE: Starting in z/OS 1.6 (HBB7709) non-SMS GDGs do NOT require
a model DSCB. If DCB=dsname is not provided, Allocation will
look for a model DSCB with the GDG base name. If not found,
Allocation will NOT fail the job, but will assume that the DCB
information will be provided from other sources at OPEN time.
See PDDB item BDC000033660 for the documentation changes to the
JCL User's Guide.
(Note that most of the information in the following Reader's Comment Form
(RCF) never made it into the manuals, so I have resubmitted the RCF.)
>From PDDB item BDC000033660:
Here is the revised documentation, which I am submitting as an RCF:
Ref: Title: z/OS V1R6.0 MVS JCL User's Guide
Document Number: SA22-7598-04
Re1: APPENDIX1.2.2.3 -- Defining Attributes for Non-SMS-Managed
Generation Data Sets
Remove the following:
"Another requirement (in addition to a GDG base entry) for a GDG is a
data set label. The system uses this label to refer to DCB attributes
and the EXPDT value when you create a new generation data set."
Add the following in its place:
"Beginning in z/OS 1.6, it is no longer a requirement that a data set
label exist in order to create a generation data set. It is now
sufficient simply to supply DCB attributes in the same manner as is
done for non-GDG data sets."
Under "DCB attributes can be supplied in one of the following ways:",
change the word "the" in point # 3 to the word "another." That is,
Remove the following:
"3. Specify LIKE= or REFDD= to use attributes from the DD statement
or specify DATACLAS to use attributes specified for the data class."
Add the following in its place:
"3. Specify LIKE= or REFDD= to use attributes from another DD statement
or specify DATACLAS to use attributes specified for the data class."
Add the following as # 4:
"4. Specify DCB attributes on the DD statement or on the DCB in the
program which creates the data set."
Under "Attributes can be supplied before you catalog a generation, when
you catalog it, or at both times, as follows:" change the word "either"
in point # 2 to the word "any." That is,
Remove the following:
"2. You do not need to create a model data set label if either of the
following is true:"
Add the following in its place:
"2. You do not need to create a model data set label if any of the
following is true:"
Add the following as letter 'c' under that point # 2:
"c. The DCB attributes are specified on the DD statement or on the DCB
in the program which creates the data set."
Re2: APPENDIX1.2.2.4 -- Creating a Non-SMS-Managed Generation Data Set
In the first sentence of the last paragraph change the word "must" to
the word "may." That is,
Remove the following:
"If a model data set label does not exist, you must use the label for a
cataloged data set."
Add the following in its place:
"If a model data set label does not exist, you may use the label for a
cataloged data set."
Add the following as the final sentence of that last paragraph:
"Alternatively, simply code DCB=(list of attributes) and supply all of
the desired DCB attributes."
Ralph Kaden
z/OS (MVS) Level 2 Support - Allocation and Scheduler
(Converter/Interpreter, Initiator/Terminator, ENF, SJF, SMF, SSI, SWA Mgr)
T/ L: 8/295-4096 External: 845-435-4096
VM: S390VM.v$i01029 MVS: PLPSC.v$i316
External email: [EMAIL PROTECTED]
Internal email: Ralph Kaden/Poughkeepsie/Contr/[EMAIL PROTECTED]
Rick Fochtman <[EMAIL PROTECTED]>
Sent by: IBM Mainframe Discussion List <[email protected]>
08/12/2008 12:04 PM
Please respond to
IBM Mainframe Discussion List <[email protected]>
To
[email protected]
cc
Subject
Re: Historical question -- GDG allocation
-----------------------------<snip>-----------------------
>>The model was required with operating systems MFT amd MVT. The model
requirement went away when IDCAMS became available.
>>
>>
>
>I don't think so!
>I've only worked with MVS & up, and I learned the hard way about models
being required.
>
>
----------------------------<unsnip>-----------------------------
As far back as I can remember, there were always two ways to provide a
model.
1. Create a zero-space dataset, with the appropriate characteristics, of
the same name as the Generation Index, on the same volume as the catalog
containing the Generation index.
2. use the DCB=dsname construct, with appropriate characteristics, on
the allocating DD statement. Many shops use this approach, pointing to a
single model DSCB that was the same name for everyone.
So, some sort of model is required, but not necessarily a model named
the same as the generation index.
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