On Thu, 17 Jul 2014 21:11:52 -0400, Thomas David Rivers wrote:
>>
>But - what's the tracklen of a "BSAM UNIX file?"
>
Given that you posted a DSLIST INFO showing UNIT=3390, I'm
calling that question hypothetical. But OPEN's not filling in DCBBLKSI
remains a mystery.
>So, does this mean you can use 32760 if the DD is not allocated to a PATH, TAPE
>or DUMMY? What do you use if the DD is allocated to one of those? What does
>one
>use then?
>
TAPE: If SL, the BLKSIZE is in the label (but what max?) If not SL, you
must supply it, by coding either in JCL or the DCB macro.
DUMMY, PATH: you must supply it, by coding either in JCL or the DCB macro.
If you happen to be a general purpose RunTime Library (would you happen
to be one of those?), you have a quandary.
If PATH=...,FILEDATA=BINARY,RECFM=U, I hope that ?SAM emulation is
as nice as for RECFM={F|V}B, and breaks the data into phony blocks
no larger than what you code. But you must supply BLKSIZE.
>That is - do we yet have an answer to the question of "how large an area should
>be allocated for a RECFM=U to ensure you have enough space for the first READ?"
>Or, is the question simply not answerable without looking at the VTOC
>(or an SVC 99 query?)
>
OPEN is *supposed* to fill it in from the VTOC.
>I'm hoping I have a bug somewhere - but this same code works just fine for
>F/FB/V/VB
>files... I'm just really surprised that the DCBBLKSI isn't filled in after the
>OPEN... in my
>pouring thru the documentation, I could only find sentences that indicate the
>DCBBLKSI
>is only filled in by OPEN for F/FB/V/VB files. This leads me to wonder,
>perhaps it
>
Documentation? Cite?
>simply isn't filled in for RECFM=U? (Which is what appears to be happening.)
>
>It just seems like, perhaps wallowing in naivite, that if you can fill it in
>for the
>other RECFMs, and it would be so darn convenient for this; that I can't be the
>first guy to stumble over it... and, if it weren't filled in, why not?
>
Really. I don't want to dive into Assembler to test. Maybe ISPF LM will
give me a hint. Rexx is just starting to handle RECFM=U.
-- gil
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