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Author Re: MAINFRAME SHOP STANDARDS (VSAM)
William M. Klein

2004-12-17, 3:55 pm


"Arnold Trembley" <arnold.trembley@worldnet.att.net> wrote in message
news:SAsvd.1089328$Gx4.509542@bgtnsc04-news.ops.worldnet.att.net...
<snip>
> I have never needed to use a VSAM RRDS file, and I'm not sure if RRDS supports
> variable length records. Obviously, variable length records are well
> supported for VSAM KSDS and ESDS files.
>


Yes, current z/OS VSAM *does* support variable length RRDS (relative) files.
Interestingly enough (hisotical trivia), this support was FIRST available for
VSAM under VSE. At the time that IBM introduced VS COBOL II, R3.0 for MVS (and
CMS), VSAM did *not* support variable length relative files. Therefore, IBM
needed to provide the SIMVRDS (Simulate Varaible Relative Data Set) run-time
option - which they continue to support today - in order to provide "full" '85
Standard conformance. I don't remember the exact year, but a couple of years
later variable length RRDS files became available for MVS and can be used today
(or SIMVRDS files using KSDS "structures" can still be used).


--
Bill Klein
wmklein <at> ix.netcom.com


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