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DA- Logical File Name Importance

 
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ksk

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PostPosted: Tue Apr 08, 2008 5:33 pm    Post subject: DA- Logical File Name Importance
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Hi All,

I have few questions on Logical file names.

1. We have some logical file names which statrts with prefix DA- like DA-INX111Y0 and DD name was used as INX111Y0.

Can anybody let me know what is the significance of DA-?

2. Some of these logical file names have been used in some JCLs and some other logical file names have been used in some other JCLs.

Is it not necessary to have all logical file names of a program in a JCL when we execute that particular program?

Regards,
KSK
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Gnanas N

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PostPosted: Tue Apr 08, 2008 6:22 pm    Post subject:
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DA might be specific to your application. What does your application documentation say for this?

OR

These are from Quick Ref on MVS.

Data Area
Destination Address
Diagnostic Application
Device Adapter in item DEVICE_ADAPTER
Direct Access
Dynamic Area
Data Analyzer
etc...
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Gnanas N

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PostPosted: Tue Apr 08, 2008 6:35 pm    Post subject:
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KSK,
Quote:
2. Some of these logical file names have been used in some JCLs and some other logical file names have been used in some other JCLs.

Code:
SELECT <logical_filename> ASSIGN TO <ddname>

Logical file name is used in program and ddname mentioned here will be used in JCL. Please rephrase your question.

Quote:
Is it not necessary to have all logical file names of a program in a JCL when we execute that particular program?

It's necessary. Are you looking something else?
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dick scherrer

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PostPosted: Tue Apr 08, 2008 8:56 pm    Post subject:
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Hello,

Quote:
Can anybody let me know what is the significance of DA-?
Probably just a naming convention for that organization or system.

Quote:
2. Some of these logical file names have been used in some JCLs and some other logical file names have been used in some other JCLs.
Please post a couple of SELECT/ASSIGNs and their DD statements from the jcl.
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Craq Giegerich

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PostPosted: Tue Apr 08, 2008 10:28 pm    Post subject:
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DA- used to be used to indicate disk files, PR- was printers etc. I don't think that these qualifiers are required in COBOL any more.
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dick scherrer

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PostPosted: Tue Apr 08, 2008 11:45 pm    Post subject:
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Hello,

Quote:
DA- used to be used to indicate disk files, PR- was printers etc.
Weren't those after the ASSIGN? My understanding (maybe mis-understanding<g>) was that the names in question here were after the SELECT and before the ASSIGN. . .
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Anuj Dhawan

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PostPosted: Tue Apr 08, 2008 11:46 pm    Post subject:
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Hi,

In 'ancient' time, Mainframes was not that 'intelligent' to understand the whereabouts of a file. There were, I assume because of shop standards, different ways to tell the system about the file, whether the file is on DASD or on TAPE. In all the files which are referred as
Quote:
DA-INX111Y0

DA should stand for Direct Access, check it, try to search using ISPF 3.14 on 'DA-', you might get some useful comment in some program.


In my shop for the files which are supposed to be OPENed in INPUT mode they used to start with
Quote:
UT-S-File name


It can be read as Utility-Only Access Sequential

Above conventions are present only in old programs (written ages ago before my birth even.. icon_smile.gif ). I think calalogue 'services' ruled out these type of needs now.
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Aaru

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PostPosted: Wed Apr 09, 2008 12:56 am    Post subject: Reply to: DA- Logical File Name Importance
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ksk,

DA stands for direct access. Even in my shop, all the dd names are prefixed by DA. I had the same doubt before and i googled to find this detail.

May be you can google and get the details. It is not site-specific as far as i know.
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Craq Giegerich

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PostPosted: Wed Apr 09, 2008 1:07 am    Post subject: Re: Reply to: DA- Logical File Name Importance
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Aaru wrote:
ksk,

DA stands for direct access. Even in my shop, all the dd names are prefixed by DA. I had the same doubt before and i googled to find this detail.

May be you can google and get the details. It is not site-specific as far as i know.


None of them in my shop are!
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Anuj Dhawan

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PostPosted: Wed Apr 09, 2008 2:50 am    Post subject:
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Hi,

I just recall it...it was some where on TAPE of my mind.. icon_smile.gif

First part in DDNAME tells the Device Class,
- UT stands for Utility (Tape or Sequential Disk)
- DA stands for Direct-Access (disk)

Second part in DDNAME tells Method of Organization
- S stands for Sequential (Printer, terminal, disk or tape)
- I, R, D stands for Disk files to be accessed randomly.


This document contains a little more information, might help,

http://publibfp.boulder.ibm.com/cgi-bin/bookmgr/BOOKS/IGY3LR00/4.2.3?SHELF=igy3sh01&DT=20011206182158
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CICS Guy

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PostPosted: Wed Apr 09, 2008 3:07 am    Post subject:
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Maybe someday KSK will report back with more information.
I do recall the UT, UR, SD and DA in the select statements for VSE COBOL (along with the actual device type- remember the 2311 disk, 2400 tape. 2540 reader/punch and the 1403?)
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Anuj Dhawan

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PostPosted: Wed Apr 09, 2008 5:04 am    Post subject:
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CICS Guy wrote:
Maybe someday KSK will report back with more information.
..then perhaps I'll give up my TAPE is not that old, I've been with Mainframes since (about) two years only..but I do recall manuals list of my archives.. icon_smile.gif
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dick scherrer

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PostPosted: Wed Apr 09, 2008 6:18 am    Post subject:
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Hello,

FWIW, this syntax still works in Enterprise COBOL:
Code:
SELECT ICE-IN         ASSIGN TO UT-S-ICEIN.
I believe it is checked, but ignored as far as having any influence on the program.
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ksk

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PostPosted: Wed Apr 09, 2008 9:43 am    Post subject:
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Thanks to all for your replies.

Dick,

Quote:
Please post a couple of SELECT/ASSIGNs and their DD statements from the jcl.


We have ASSIGN clauses as shown below.

SELECT YB4 ASSIGN TO DA-INX1....
SELECT TB4 ASSIGN TO DA-INX1....

we have these type of assign clauses 201 in a single program but only these 2 files were used in the JCL. JCL has DD names like below.

//INX1.... DD DSN=

//INX1.... DD DSN=

Like this only, either 1 or 2 file names have been used in one JCL for this particular program. This program has been used in many JCLs and out of 201, some other 1 or 2 file names were used in some other JCL and so on....

But all 201 have not been used in any single JCL. And these programs and JCLs are in production now.

I could find the following explanation for the above files in the program.

INCREASED LRECL FROM 130 TO 185 FOR YB4/TB4

gnanas,

We don't have any documentation on this.

Anuj,

Yes, we have also have some file names with UT-S-. These programs have been written in mid 90's not log long time back.
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Anuj Dhawan

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PostPosted: Wed Apr 09, 2008 10:37 am    Post subject:
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Hi,

Just for an experiment, use DD name without DA- in SELECT..ASSIGN, & let us know what happens at your end. I hope you would get (better) answer.
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dick scherrer

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PostPosted: Wed Apr 09, 2008 11:23 am    Post subject:
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Hello,

Quote:
But all 201 have not been used in any single JCL.
I would expect not. . . What does the "exec pgm=" for this program look like? Are there one or more parms?

It was quite common to have code that had many file definitions that were not used in every run. Often, these were controlled by run-time parameters on the exec statement. Another way to control processing was reading some control info from some file or database table (or queue) and opening files accordingly.

Quote:
SELECT YB4 ASSIGN TO DA-INX1....
SELECT TB4 ASSIGN TO DA-INX1....
Yes, these are also acceptable to the compiler. They should cause no concern.
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ksk

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PostPosted: Wed Apr 09, 2008 11:41 am    Post subject:
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Hi Dick,

Yes, in the Exec statment, PARM parameter was used as below.

PARM='B4&SRV'

and SRV=' REFRESH '.

Regards,
KSK
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dick scherrer

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PostPosted: Wed Apr 09, 2008 11:48 am    Post subject:
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Hello,

It will probably help you if you look at the code and see how that value is processed in the program.
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ksk

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PostPosted: Wed Apr 09, 2008 12:19 pm    Post subject:
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Dick,

Thanks for the replies. Yes, this PARM value was used in the program using EVALUATE and only some of files have been processed depending upon condition.

Regards,
KSK
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dick scherrer

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PostPosted: Wed Apr 09, 2008 8:32 pm    Post subject: Reply to: DA- Logical File Name Importance
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You're welcome - good luck icon_smile.gif

Someone will be here if there are more questions.

d
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