IBM Previews z/OS 1.8 for Mainframe Shops

Published: February 28, 2006

by Timothy Prickett Morgan

If you like the mainframe flavor of alphabet soup, you are probably going to get a good meal out of the z/OS V1.8 and z/OS.e V1.8 preview that IBM put out this week. While z/OS V1.7 was just launched last September to coincide with the ramping up of the System z9 mainframes that were announced in July, mainframe customers always have things they need Big Blue to do to make their z/OS environments better, stronger, and faster.

The MVS-OS/390-z/OS platform stretches back to 1974, with the System/370s, and even though z/OS is a perfectly modern platform in that it supports a POSIX-compliant Unix runtime environment, a Java environment, and lots of different compilers, databases, and transaction monitors, the mainframe--and z/OS in particular--has a different way of speaking about itself. That's what I mean about alphabet soup. The preview is chock full of abbreviations for system features and functions, and in a particularly dense document, it can be mind-numbing to read. (You should probably give it a read, though, which you can do by clicking here.) There are a million little tweaks in this announcement, and one of them undoubtedly will affect you.

This one affects everyone, though. With z/OS V1.8, a z/OS image will be able to support up to 4 TB of real memory--not that IBM can deliver a mainframe with that much main memory--at least not yet. (Maybe in a year or two.) That 4 TB upper limit for main memory will only be available on the new System z9 mainframes. Initially, it looks like the System z9 will get 512 GB for a single z/OS image when z/OS V1.8 ships, even though the guts of the operating system can support more. (Larger memories will probably be available on a special bid basis, as IBM always allows--for a price.) Older zSeries 990 mainframes will be able to support up to 256 GB of main memory, up from 128 GB. Making more physical memory available will cut down on paging and swapping and allow workloads to grow without thrashing.

Here's a quick overview of the main features of z/OS V1.8 and its cut-down, lower-priced version for small mainframes. z/OS.e V1.8. As has been the case for the past ten years, IBM is trying to keep the mainframe as the hub of data processing, and with z/OS V1.8, the company is making good on its promises to deliver XML services that are centrally controlled through the mainframe. This forthcoming feature, called z/OS XML System Services, is an XML document parsing engine that has been optimized for the mainframe and is expected to be used by software vendors and middleware makers who are using XML as the glue to hook together pieces in a distributed application. (These are called Service Oriented Architectures nowadays, but it is the same old same old. SOA and APPC-APPN are not really all that different in concept.) In any event, z/OS XML System Services, or z/OS XML for short, will come out in z/OS V1.8 with an assembler language interface, and will be backcast to z/OS V1.7, too. In a future z/OS release, IBM plans to add an interface to the mainframe version of its C/C++ compilers.

z/OS V1.8 will also include a new LDAP server, one that has more affinity with the Parallel Systeplex clustering on mainframes that is very popular at big mainframe shops. IBM is adding caching features to speed up LDAP performance, and will be storing LDAP directory entries in the Unix System Services part of z/OS. And, to the great joy of many, RACF will get support for passwords that are longer than eight characters long, often called pass phrases; passwords in z/OS V1.8 can be as much as 100 characters long, which means you can put in your favorite Shakespeare quote now. On the availability front, the DFSMS hierarchical storage software for z/OS V1.8 will allow fast replication of data sets (what you and I would call a file) to IBM disk arrays and tape drives.

In a statement of direction, IBM warned that z/OS V1.8 would be the last mainframe operating system that would support communication between a Hardware Management Console (HMC) and the Hardware Configuration Definitions (HDC) elements on the mainframe using the APPC features inside the SNA protocol. In 2007, when the next release of z/OS comes out, HMCs will only speak TCP/IP. z/OS V1.8 will also be the last release to have C/C++ IBM Open Class (IOC) dynamic link libraries. Application development support for the C/C++ IOC library was withdrawn with z/OS 1.5, and runtime support will be removed in the release that follows z/OS V1.8 in 2007. If your applications use those libraries, they won't run.

IBM says that z/OS V1.8 will run on the z800, z890, z900, z900, and System z9 machines, while z/OS.e V1.8 will be supported on the z800 and z890. IBM did not say when z/OS V1.8 would be available, but it seems likely that it will ship this year, and probably whenever the System z9 Integrated Information Processor (zIIP) database engines start rolling out this year.