On Mon, 2008-09-08 at 22:05 -0400, Pete Massiello wrote:
RRN is a great concept used in the 70s and early 80s, really before logical
files. The problem with RGZPFM is that it will change the location of the
record in the file. In a RRN direct access, when you want to read customer
number 6000, you read record 6000 and that is the correct record. If you do
a RGZPFM, then the record for customer number 6000 is no longer stored in
record 6000.

Whenever I find programs accessing records by RRN, I usually try to find the
programmer who wrote it and bring him/her up to the roof and throw him/her


In all seriousness, it was a very quick and efficient way to access
records before logical files. The big issue is when the "key" that you are
using on the RRN has large gaps in its value, then you will have the same
number of empty or deleted records between the real records.

I remember back around '82 delivering bespoke software to a customer
only to find that his System/36 disk space was insufficient even to load
his customer file. So, a quick change, replacing an indexed file of
customer comments with a linked list of comment lines--addressed by
rrn--rooted in the customer record. Can you believe it?



-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Mark S. Waterbury
Sent: Monday, September 08, 2008 3:43 PM
To: Midrange Systems Technical Discussion
Subject: Re: Prohibit RGZPFM because of RRN access.

Hi, Rob:

So long as those RRNs are never stored anywhere else, (e.g. in any other
files, to "point to" records in this file), then what's the harm in
allowing a RGZPFM? I think RGZPFM requires "exclusive" access to the
file, so none of your applications can be actively using this file, when
the RGZPFM takes place; or the RGZPFM will get:

CPF3202 File XXXXXXXXXX in library YYYYYYYYYY in use.

So long as the application does not close the file, and "hang onto" any
RRNs, and then re-OPEN the file and expect the records to still be there
in the same place, you should be okay.

Or, am I missing something?


> rob@xxxxxxxxx wrote:
If one routinely access a file by RRN is there a way to CHGPF or some such

thing to prohibit RGZPFM against that particular file?

Rob Berendt

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