IBM United States Software Announcement
210-008
IBM is a registered trademark of International Business Machines Corporation
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Details on the performance and scalability enhancements intended for z/OS V1.12:
• DFSMS is planned to support additional data set types, including sequential (both
basic and large) data sets, partitioned (PDS/PDSE) data sets, catalogs, and BDAM
data sets in the extended addressing space (EAS) on an EAV. Support is also
included for generation data groups (GDGs) and VSAM volume data sets (VVDSs).
Overall, EAV helps you relieve storage constraints as well as simplify storage
management by providing the ability to manage fewer, large volumes as opposed
to many small volumes.
• Support is planned to make all data sets used by DFSMSrmm eligible for allocation
in the extended addressing space of an EAV. This includes the DFSMSrmm journal
and dynamically allocated temporary files.
• In z/OS 1.12, DFSMSrmm support for IPv6 is also planned.
• Language Environment provides support for C/C++ to access alternate indexes
(AIXs) for extended format VSAM key-sequenced data sets (KSDSs) that reside in
the EAS on an EAV.
• JES2 will be designed to allow both spool and checkpoint data sets to reside in
the EAS on an EAV, making it possible to place both spool and checkpoint data
sets anywhere on an EAV and to define spool data sets up to the maximum size of
1,000,000 tracks (approximately 56 GB).
• JES3 will be designed to allow spool, checkpoint, and Job Control Table (JCT) data
sets to be placed anywhere on an EAV.
• Some workloads require an increasing number of open data sets. In z/OS V1.12,
the BSAM, QSAM, and BPAM (basic and queued sequential, and basic partitioned
access methods) and EXCP (execute channel program) processing will be designed
to support the use of an extended task I/O table (XTIOT) with uncaptured UCBs,
and support data set association blocks (DSABs) above the 16 MB line. This is
expected to allow more data sets to be allocated by an address space and to
provide virtual storage constraint relief for DASD and tape data sets.
• The SNAP/SNAPX services and dump processing (including that for SVC,
SYSABEND, SYSMDUMP, and SYSUDUMP dumps), and the AMASPZAP program are
planned to support XTIOT.
• The Program Management Binder will be designed to support data sets having
XTIOT entries.
• TSO/E will be designed to XTIOTs, uncaptured unit control blocks (UCBs), and
DSABs above 16 MB for data sets allocated by programs.
• RACF will be designed to support XTIOTs, uncaptured UCBs, and DSABs above 16
MB for data sets allocated by programs.
• DADSM and CVAF changes are planned to support XTIOTs, uncaptured UCBs,
and DSABs above the 16 MB line. This is intended to help you take advantage of
those functions to allow more concurrently open data sets and provide for virtual
storage constraint relief.
• OAM is planned to provide API support for the Object Storage and Retrieval
function (OSR) to run in a CICS threadsafe environment. This is intended to
allow exploiters to take advantage of the improved multitasking and throughput
capabilities provided by threadsafe programming. Additionally, the Volume
Recovery utility will be designed to improve performance in certain situations
when recovering object data stored on optical and tape media. Improvements
are expected to be most noticeable when recovering a backup volume containing
objects with primary copies in a large number of different collections on a large
number of different volumes.
• Large (1 MB) pages were introduced in z/OS V1.10. In z/OS V1.12, the nucleus
data area is planned to be backed using 1 MB pages. This is intended to reduce
the overhead of memory management for nucleus pages and to free translation
lookaside buffer (TLB) entries so they can be used for other storage areas. This
is expected to help reduce the number of address translations that need to be
performed by the system and help improve overall system performance.
• In z/OS V1.7, support was introduced in DFSMSdfp for large format sequential
data sets (DSNTYPE=LARGE). In z/OS V1.8, Language Environment added
support for these data sets using noseek (QSAM). Support for seek (BSAM) was
limited to data sets no larger than 64K tracks on any volume when opened for
read. In z/OS V1.12, seek (BSAM) support is planned to be extended to data sets
