On Thu, 19 Sep 2013 11:26:54 -0500, Paul Gilmartin <[email protected]> wrote:
>On Thu, 19 Sep 2013 10:07:48 -0500, Doug Henry wrote:
>>
>>This is true. In SC26-7407-07 DFSMS Implementing System-Managed Storage it
>>says
>>
>>"Ensured Data Integrity on New Allocations
>>The system provides data integrity for newly allocated data sets that have
>>not been written to. For these data sets, whether SMS managed or non-SMS
>>managed, DFSMSdfp writes a physical end-of-file character at the beginning of
>>the data set when space for the data set is initially allocated.
>>
>We have evidence in this thread that what that manual says is untrue.
>If DFSMSdfp had written the EOF "when space for the data set [was]
>initially allocated", Barbara would have had zero directory blocks
>reported. It's possible that DFSMSdfp is coded to bypass writing
>the EOF if DSORG=PO, assuming (incorrectly) that the directory will
>be formatted, supplying the EOF.
>
Obviously Barbara intentionally didn't request any directory blocks. I would
expect and I am sure she did also that would produce a JCL error.
But if you do a valid allocation what the manual says is correct.
I allocated a 1 track non-sms managed pds (we have SMS Active on our systems).
Of couse I allocated with a directory block specified.
//SYS00188 DD DSN=MY.TESTPO,DISP=SHR,UNIT=3390,
// DCB=(RECFM=FB,LRECL=20,BLKSIZE=20),VOL=SER=IPLXXX,
// SPACE=(TRK,(1,,1))
Then dumped it with FDRDSF :
FDR520 PRINTING FROM DEVICE TYPE 3390-9 TO OUTPUT DDNAME TAPE1
FDR521 CYLINDER 000150 TRACK 0001 ------------------ RECORD ZERO
0096000100000008 -- DATA 0000000000000000 ------
FDR522 COUNT FIELD 0096000101080100
000000 FFFFFFFF FFFFFFFF
*........ *
000000 000EFFFF FFFFFFFF FFFF0000 00000000 00000000 00000000 00000000
00000000 *................................*
000020 00000000 00000000 00000000 00000000 00000000 00000000 00000000
00000000 *................................*
LINES 000040-0000E0 SAME AS ABOVE
FDR522 COUNT FIELD 0096000102000000 -- END OF FILE <count field is zero
ie EOF.
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