A few years ago, inspired by a beverage wager, I allocated a large PDSE,
FB-256, and started using it to store output listings. Every day it would
accumulate about 300 output files.
After I accumulated about 2K members I decided to make it interesting. I
wrote up a sort job that read a test file then wrote multiple output members
to this PDSE. I kept adding DD cards to hasten collecting on the beverage.
At its peak my sort job wrote 10,000 members in one pass. I kept rerunnig
this job, changing the output member name, always adding members at the
front of the file. I kept this up for a few weeks, can't remember the final
number of members, but my colleague paid up.
We never did experience any problems and we did spot check the data from
time to time.
P.S. Belated thanks to Frank Yeager and his DF/SORT web site for the
inspiration to create a lot of records with incrementing sequence numbers.
I used this technique to generate 10,000 DD cards and a like number of
OUTFIL OUTREC statements. When I have some (more)time to goof around I'll
try this again to see how large a number of output members I can write in 1
passm maybe 32K for grins. There's probably some limit on DD cards that I
can't recall at the moment.
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf
Of Thompson, Steve
Sent: Wednesday, February 10, 2010 2:18 PM
To: IBM-MAIN@bama.ua.edu
Subject: Re: PDS vs. PDSE
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:ibm-m...@bama.ua.edu] On Behalf
Of John R. Ehrman (408-463-3543 T/543-)
Sent: Wednesday, February 10, 2010 1:47 PM
To: IBM-MAIN@bama.ua.edu
Subject: PDS vs. PDSE
PDSEs have been available for a long time, and provide many advantages over
PDSs. Why are people reluctant to use PDSEs?
John Ehrman
-----
>From my experience, it is a time bomb waiting for the "directory" to get
"fragmented".
And if you are using objects, lots of luck.
If you want to recreate the situation of which I refer, build a "listing"
PDS/E and run your HLASM Listings out to it. In my experience you will
possibly work OK with this for about 3 months (I was doing 3-20 assembles
per work day) and then things stop working. The only way out is to delete it
and rebuild it. I went back to PDSes and defrag/degas (at short intervals).
The SYSLMOD output from BINDER gets even more screwed up. And the only way
out was delete and rebuild.
And unless you have them backed up, you just lost the contents.
Now maybe the problem is, I set them up with a SINGLE extent (about 75
CYLINDERS).
But this is why I don't use them in development. For a relatively static
(from my perspective) file, works OK.
Regards,
Steve Thompson
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