Well shoot, it looks like DFSMS OPEN merges the SECONDARY space quantity
into the JFCB but not the primary, perhaps because the secondary might be
needed for space extension, but there's really no use for the primary
quantity after initial allocation? Seems odd to me.
The primary quantity is not saved anywhere after allocation (except for
VSAM) so it won't appear in the merged JFCB when opening an existing
dataset. If you specified a SPACE parm on the DD statement, the
primary value will appear in the JFCB, but is the value from the parm,
which may have no relation to the actual primary used when the ds was
allocated.
Where does ISPF 3.2 get it from? Okay, it gets it from FAMS. Where does FAMS
get it from?
ISPF 3.2 does not display the primary allocation. It shows
1st extent cylinders: 25
Secondary cylinders : 5
but the first extent size is not necessarily equal to the primary
allocation. The primary request can be satisfied in up to 5 extents
(sometimes more) if the volume is fragmented, so the first extent is
equal to or less than the primary allocation request.
Is DS1LSTAR the last used track and block
- on the volume on which it appears in a DSCB-1?
- on all volumes that the dataset occupies?
Does that imply that a QSAM or PDS (non-PDSE) dataset is limited to 32,767
tracks? Or 65,535 tracks?
Sorry if this is a dumb question but the sum total of the documentation is
"Last used track and block on track (TTR). Not defined for VSAM, PDSE, and
HFS." Or is it documented somewhere besides DFSMS Advanced Services?
Prior to z/OS 1.7, most dataset types are limited to 65535 tracks per
volume. Some types (PDS) are limited to one volume, so they have an
absolute limit of 65535.
From the 1.7 Using Data Sets manual:
"Data sets that are not limited to 65 535 total tracks allocated on any one
volume are:
O Large format sequential
O Extended-format sequential
O UNIX files
O PDSE
O VSAM "
"Large format" is new in 1.7, and is a standard sequential (PS) dataset
that can exceed 65535 tracks. See the 1.7 DFSMS manuals for details.
For such datsaets, the high TT is extended with another (non-contiguous)
byte
--
Bruce A. Black
Senior Software Developer for FDR
Innovation Data Processing 973-890-7300
personal: [EMAIL PROTECTED]
sales info: [EMAIL PROTECTED]
tech support: [EMAIL PROTECTED]
web: www.innovationdp.fdr.com
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