Operating Systems

When z/VSE 4.2 was announced and delivered, the extended task support—255 to 512—received significant attention among the z/VSE users, as it was an important extension and enhancement. But z/VSE 4.2 also contains many other important enhancements.

The z/VSE real memory capability has been extended from 8GB to 32GB. Many users running a large z/VSE image with data in memory via VDISK or Data Space will now dramatically extend the data in memory concept. More data in memory means fewer real I/Os, better performance, improved throughput, and better system utilization. In a 32GB real environment running z/VSE with NOPDS (No Page Data Set) and massive amounts of data in memory, online response times and batch run-times will be the best they can be.

A VSAM enhancement that may have passed under the radar is the ability for reusable KSDS data sets to be defined as Extralargedatasets. This is a real asset for those of us who process very large data sets.

A significant POWER enhancement is the PDISPLAY LST,CRAGE>hhmm command for displaying older queue entries; very handy for cleaning up the queues of old entries using a simple REXX routine to display, report, and then delete.

Another POWER improvement is the ability to produce a message reporting a queue alteration. For more information on this and additional improvements, see the POWER Version 8 manuals.

For users of VSE/OLTEP, it’s the end of the road, as OLTEP is no longer supported. Few, if any, people still use OLTEP. For trivia, OLTEP stands for OnLine Test Executive Program.

Seven new hardware crypto commands extend the users’ ability to control and manage the crypto environment. Having not been a user of hardware crypto, I’m unsure how important this may be; however, it sure seems impressive.

The ability to use a full-function Lightweight Directory Access Protocol (LDAP) server for z/VSE sign-on control is a major enhancement for many folks. I still think that anyone who has a 64-byte userid and a 64-byte password will never remember them. But I can see where it’s the ultimate security, when even the user can’t log-on. Seriously, this is a major enhancement, despite my attempts at humor.

Parallel Access Volume (PAV) support implementation in z/VSE 4 is great news for users of the DS6000 and DS8000. The show-stopping feature is the ability to have multiple, concurrent I/Os ongoing to the same volume from the same or multiple z/VSE hosts. If data in memory somehow isn’t the ultimate solution for your environment, then PAV support would seem to be mandatory.

Two other disk enhancements address SAN Volume Controller (SVC) and Flashcopy Space Efficient (SE) Support. See the announcement for additional information.

z/VSE 4 also supports a feature known as Signal Shutdown, or Signal Quiesce. The SYS IPL command has a new parameter, QUIESCE=NO|YES, to enable or disable the function. NO is the default, and means that z/VSE won’t honor a command from the Hardware Management Console (HMC) to begin system shutdown. YES implies that it will honor the request and that you, the z/VSE systems programmer, have written a procedure to perform that shutdown. No shutdown facility is supplied with the system. Many z/VSE installations already have an automated shutdown written in REXX or GREXX. When running one or more native z/VSE systems on the same CPU complex, implementation of this facility would enable the operator to issue an IML from the hardware console, and then the HMC would issue the Signal Shutdown to each z/VSE system; each z/VSE system would execute the REXX shutdown procedure. So, basically a hardware command could implement a controlled shutdown.

z/VSE 4.2 is in every way a major release with major new function; hopefully, everyone is making plans to install it as soon as possible.

Thanks and Best Wishes

From the z/VSE community, a very special thanks and best wishes to Jerry Johnston of IBM upon his retirement. Jerry has been an advisor, confidant and very special friend to z/VSE users everywhere, and we all congratulate him on a job well-done. We will miss his sage advice, humor, and guidance. Thanks, Jerry, for all you have done for the z/VSE community.

Good luck with your move to z/VSE 4.2. Thanks for reading this column, and see you all in the next issue!