Innsbruck z/OS and Storage Conference – Day 2

(Originally posted 2005-04-13.)

Session z05: z/OS Sysprog Goody Bag, Presenter: Bob Rogers

Bob is always good value. This time was no exception.

Consoles Restructure undertaken because a problem cause analysis for Parallel Sysplex showed Consoles as being the
weakest link. Also there was a need to remove some constraints, such as the 1-byte console ID, plus the need to reduce the scaling inhibitor of metadata in large sysplexes. z/OS R.7 introduces Phase 1B. This is the last release to support programs that use 1-byte console IDs, but it will only support them if they were assembled on a previous release. R.5 provided a program to track 1-byte console ID usage.

In R.7 Program Objects’ metadata can be compressed using hardware compression. The program itself isn’t, which allows the program executable to be run on prior releases. But you can’t reprocess (using the Binder APIs) on a prior release – because this metadata couldn’t be decompressed. Also the Binder can resolve relative branches between CSECTs in Program Objects. These are instructions like BRC, BRAS,BRCL, BRASL and LARL. This became important
with the introduction of “Long Relative Branch”. BRC and BRAS are of course “old” 2-byte immediate operand
instructions. The others use 4-byte immediate operands. LARL is in fact not a branch but a Load Address Relative
(Long). Note: This is “Program Object” only.

In R.7 SVC Dump does not dump unreferenced pages – which improves its performance. Also it puts out performance statistics. This is obviously in support of the fact that we’re going to have to dump more and more data.

In R.7 SDSF has a new JES2 Resources dialog. This lets you display resource (eg BERT) usage, see the limits in force
(and change them) and see historic detail. It should help avoid running out of resources.

Peter Relson (who I know to be excellent) worked for 6 months to add robustness to the Health Checker (which was

missing from the “free download” version). So the R.7 version should be more robust. Also a “check interface” was
added that should allow other products (both IBM and OEM) to add their own checks. SDSF now has a panel to display
and control active checks. New checks are in the areas of GRS, Consoles, SVC Dump, XCF, Unix System Services, RACF.

Bob asked if anyone was playing with zAAPs. At this point no-one in his audience admitted to it. Which I think chimes
with my view that people will later this year.

Bob confirmed that 32-way images will be supported from June 2005. DB2 will need PTFs for Query Parallelism – so
that its code to split queries according to the number of engines will cope with more than 16 engines.

Bob is hearing that some other software vendors are not including zAAPs in the capacity they base software licence
charges on. He did not name them but I mention this because it means that it’s not just IBM that’s doing this.

In R.6 TSO TEST has been enhanced, after a long period of inactivity. For example it now uses an IPCS-supplied table
to ensure current instructions are supported. Similarly new bits in the PSW (bits 12 and 31, in particular) are
supported. Its instructions are also displayed in a more readable format.

An installation can now specify the SMF buffer size using BUFSIZMAX(nnnnM), which ranges from 128MB to 1GB. Also
BUFUSEWARN(percent) in range from 10 to 100% so you can vary when buffer usage warning message is produced.

Bob also discussed the R.6 implementation of additional Linkage Indexes (LX) for z890 and z990. MQ and DB2 have PTFs to support this. A subsequent stage is Reusable LX’s. R.6 has the support but it will take a little longer for the subsystems to take advantage of this. Basically a sequence number is associated with a given LX so that the right version is used.

Also mentioned was the R.6 WLM enhancement to support nested DB2 Stored Procedures better: WLM attempts to start
server regions more aggressively if dependent requests have to wait. I’ve been involved in a couple of situations
this would’ve helped with. Also WLM (rolled back into R.4) has enhancements for placement of Websphere stateful

1 customer admitted to running DB2 Version 8. I think the same question next year would have many more takers.

In a previous release Format 0 virtual channel programs were translated into Format 1 real channel programs. In R.6
Format 1 virtual channel programs are also translated into Format 1 real channel programs.

In R.6 C/C++ applications can now exploit 64 bit virtual.

Session TSS09: VSAM RLS 64 Bit Buffering Enhancement, Speaker: Terri Menendez.

A good presentation on work in progress to convert RLS from using the SMSVSAM dataspace to 64-bit virtual. You will
be able to implement this selectively. Also the management algorithms are enhanced.

After lunch I have to admit I took off for the hills. Innsbruck has a nice bus service that gets you out of the city into the countryside very quickly. And after walking a mile or so Innsbruck disappeared behind some hills. So you can get some solitude and beautiful views very quickly.

Published by Martin Packer

I'm a mainframe performance guy and have been for the past 35 years. But I play with lots of other technologies as well.

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