On Sun, 19 Jun 2022 20:04:47 +0200, Bernd Oppolzer wrote:
> ... That is, if you do fopen ("dd:outfile","wa"),
>a file allocated to OUTFILE which has some records already (in a block which
>is not filled up completely) will be filled before the next empty block is
>allocated.
>
>At least, this is my understanding, and everything else would be a shock for
>me.
>
I'm astonished. Why then the restriction:
<https://www.ibm.com/docs/en/zos/2.5.0?topic=parameter-disposition-qsam-data-sets>
Do not code DISP=MOD if the data control block (DCB) specifies RECFM=FBS and
the data set is processed by QSAM. If you do and a block is shorter than the
specified block size, QSAM assumes that the short block is the last block and
starts end-of-file processing. By this action, QSAM can embed short blocks in
your data set and so affect the number of records per track.
(Sounds like non-anglophone usage.)
>There should be no difference in behaviour (in principle), no matter if you
>are writing to a classic MVS dataset or to a USS file.
>
In UNIX, the kernel completes the partial block. Classic access methods don't.
--
gil
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