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z/OS 2.2 Supports a Variety of Upgrades


In January, IBM previewed z/OS V2.2, which z/OS Development organizations worldwide worked on for two years. Working roughly west to east, the z/OS Development team in Santa Teresa, California; Tucson, Arizona; Boulder, Colorado; Rochester, Minnesota; Toronto, Canada; Endicott and Poughkeepsie, New York; Raleigh, North Carolina; Boeblingen, Germany; Moscow, Russia; Beijing, China; and Perth, Australia; has put together a variety of functions meant to leverage new hardware facilities, take better advantage of existing ones, and provide a vital platform for subsystem and application development.

Someone—you know who you are—asked me whether I could write an article about my favorites. Now, I know these won’t be everyone’s favorites. I know these won’t be everyone’s favorites. I’ve asked many customers about the “most important” functions are in our releases for years, and I’ve been rewarded a wide variety of answers.

Working in Poughkeepsie, I rub shoulders with many of the top hardware designers in the world. They tell me physics has its limits. I knew that, of course, but they have supporting pictures, scanning electronic microscope shots to count the atoms in the layers of the transistors on the chips. Those transistors just aren’t a lot of atoms thick these days. As splitting atoms inside a computer intuitively seems as though it might be a bad idea, software plans have changed dramatically in the face of these limits over the past several years.

In every release, we need to act in concert with the hardware teams to get the performance and throughput we all need. The marketing team calls this “synergy.” This isn’t new, but the increasingly pervasive level of integration across hardware, firmware, hypervisor, OS, middleware and even applications optimized using new compiler levels is higher now. This isn’t only for processor hardware. A lot of these are done in conjunction with IBM’s disk hardware..

Compression, Software and Performance Enhancements

This is a long way of saying many of my favorite functions are “invisible.” People will have worked on some of them for years, but many will never see the light of day outside technical conferences and filed patents.

More visible ones, though, include more exploitation of zEnterprise Data Compression, extending I/O priority into the fabric, zGlobal Mirror (also known as Extended Remote Copy) write pacing, new vector (also known as Single Instruction, Multiple Data) instructions, and new uses for the far-faster encryption coprocessor (also known as the Central Processor Assist for Cryptographic Functions) in the z13 processor. Maybe it’s just the computer nerd in me, but I like these.

Then, there are software-only functions. Making it easier to manage z/OS systems is the focus for the z/OS Management Facility (z/OSMF), planned as a base element of z/OS V2.2. Its enhanced and enlarged application suite should address a number of customer and user group requirements. But, as they say on late-night TV, “Wait, there’s more!” Other things meant to make life easier are planned for z/OS V2.2.

JES2 has historically been far more popular than JES3, but some of us learned how to use systems in JES3 environments. Transitioning to JES2 was challenging already, with its new Job Entry Control Language, commands, initialization statements, and so on. On top of that, JES2 lacked JES3’s deadline scheduling and dependent job control capabilities. Analogs to these powerful ad hoc scheduling functions, but with more-modern execution and better usability, are planned for z/OS V2.2 JES2. No more need to log on when CPU time is cheap just to type “submit” and hit enter.

Also for JES2, I’ll add dynamic checkpoint tuning and expansion to the list. No need to monitor and set HOLD and DORMANCY parameters and try to find the best overall compromise or a set of compromises for different times of day sounds like a good thing. This is what computers are for; managing by feedback loop is something they do very well. In addition to fewer cold starts, dynamic checkpoint expansion means fewer change control windows, spool offloads and spool reloads, and should help availability and usability both.

When Generation Data Groups (GDGs) were originally designed, nearly nothing ran once a business day, and 255 generations was often enough for those things that did, considering weekends and holidays. Now, lots of things run more than once every day, and this limit seems unnatural. A new extended format GDG data set type supports up to 999 generations, more than enough for two a day, every day, for a year.

For performance, Control Area (CA)-level locking for VSAM record level sharing is the next step for the Data Facility Storage Management Subsystem team’s undeclared war on catalog constraints. Its goal is to help overall VSAM performance by holding less data under serialization more often. There is also support planned for many more z/OS UNIX System Services threads, better z/OS File System (zFS) performance, and DFSORT exploitation of high-performance FICON for better I/O performance.

Availability and Security Upgrades

A lot of the work done to improve availability also goes unheralded. After all, you expect your car to start and run. You should expect the same of IBM computing systems. Hardware and software teams alike focus on both planned and unplanned outages. Some of the visible planned z/OS V2.2 functions include better subsystem initialization processing to help avoid typo-induced IPLs, multi-target Metro Mirror (PPRC) to give you two levels of insulation against disk failure, and allowing the LOGREC data set to be deallocated so you can remove it or move it.

A while back, a customer council defined what they termed the “storm drain” problem. Suppose you have two servers and a load balancer that takes response time and available capacity into account. Normally, this works well, and is a more effective technique than simple round-robin balancing schemes. Now, suppose one server has a problem that instantly fails every transaction it’s sent. Hey, just look at that response time. What does the load balancer do? It doesn’t know about the problem, so it sends that server even more work.

A server health factor was added to Enterprise workload manager (WLM) routing recommendations, used by Communications Server’s Sysplex Distributor to guide routing decisions. Another service was added that a server could use to, in effect, tell WLM, “I don’t feel well…send me less work.” In z/OS V2.2, we plan to let one server to, in effect, tell WLM “that other server is not feeling well, so send it less work.” XCF is planned to exploit this when servers are not keeping up with their XCF messages, to reduce the number of situations that can affect an entire Parallel Sysplex.

There are a few exits most people need to run practical z/OS systems, for which assembler coding skills are necessary. One is the SMF step initiation exit used to set memory limits, IEFUSI. In z/OS V2.2, a new parmlib member is planned to let you specify, for common variations, which storage limits should apply for 24-, 31- and 64-bit storage. This should allow many customers to be able to get rid of their assembler language IEFUSI exits.

The Generic Tracker function, GTZTRACK, is used for a number of things including migration health checks. In z/OS V2.2 the tracker is planned to write a new SMF Type 117 record so that you can use SMF postprocessing to find tracked events over arbitrary periods of time, not just the life of an IPL.

More SMF data is planned to simplify accounting and help improve security. Job ID information in data set activity (Type 14 and 15) records, more lightweight directory access protocol auditing (Type 83), and BCPii auditing (Type 106) are planned for z/OS V2.2 Also on z/OS V2.2, we plan to make it possible to have the system sign sets of SMF records in z/OS V2.2. This can provide tamper detection capabilities for SMF data, which for many forms a crucial repository for auditability.

It’s worth mentioning read-only auditor support for RACF, a new ROAUDIT user attribute intended to provide a “look, but don’t touch” capability for auditors, which can help improve separation of duties between auditors and security administrators.

More to Come

For application development, new optimizations for z/OS V2.2 XL C/C++, also available via a web deliverable for z/OS V2.1, and in COBOL, Java and PL/I are all planned to let you take advantage of the latest hardware, with “just a recompile.”

IBM recognizes that recompilation and retesting are nontrivial, but accumulated gains from several processor generations can tip the balance. For C/C++, new function to place assembler code inline is planned, too. A new web enablement toolkit will be designed to provide a JSON parser and HTTP/HTTPS protocol enabler, both planned for this year in PTFs for z/OS V2.1 and z/OS V2.2. Finally, with z/OSMF becoming a base element of z/OS, in V2.2 you can rely on the REST APIs it provides being present, including some new file and data set APIs.

Last but not least, Communications Server will be designed with new support for National Institute of Standards and Technology SP800-131A, Resolver enhancements and Transport Layer Security session reuse. This, in addition to expanding the Configuration Assistant to address TCP/IP configuration, going beyond the policy support it already provides, and the RDMA Over Converged Ethernet enhancements available on z13 processors.

This is some of what was described in the z/OS V2.2 preview announcement. “But, wait! There’s more!” Look for an availability announcement later this year.

John Eells is a former MVS and OS/390 system programmer who also worked in ServerPac design. Now a senior software engineer in IBM Systems, his current assignments include z/OS technical marketing, future release planning and strategy.



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