Back in February, IBM published a preview of a new release of its flagship mainframe operating system, z/OS 1.11. Let's take a look at what is coming
Improvements to IBM z/OS Health Checker
IBM continues to strengthen the z/OS Health Checker. The more robust checker seems to serve the dual purposes of alerting customers to potential migration problems as well as simplifying system administration for persons new to the mainframe.
In z/OS 1.11, IBM will add health checks to validate a shop's AutoIPL policy and look for the obsolete VSAM attributes IMBED and REPLICATE in catalogs. Another check might result in CPU savings as it looks for obsolete entries in the static resource list kept in CSECT IEAVTRML.
According to the document, the list gets checked during each task and address space termination, which happens fairly often in an active system. Otherwise, there's a new option to check an installation's Dump Analysis and Elimination (DAE) settings against IBM's recommendations. Knowing what DAE does for -- and to -- us, I would examine IBM's recommendations carefully.
The migration check continues to be a great way to make sure your plans align with IBM's. In z/OS 1.11, migration checks look for some networking options that are due to be removed soon. There is also some checking for DFSMSrmm and a notification of a system still using an External Timer Reference when it is able to use Server Time Protocol (STP) which is the preferred direction. More memory above the 4G bar z/OS 1.11and associated products move more functions above the 4G bar. New Language Environment options for 64-bit Java and C++ applications will allow them to use large (1M) pages, which simplifies virtual storage management and overhead. In addition, Global Resource Serialization and TCP/IP move blocks above the bar for improved throughput. Lastly, there's a new parameter to the LOAD macro that allows application programs to load tables above the 4G bar directly instead of having to copy them up there. The restriction against executing instructions above the bar still stands.
New 64-bit memory usage fields in Systems Management Facility records will help your local capacity planner.
The new operating system will not increase the number of Unit Control Blocks beyond 64,000. As per IBM's stated direction, we will get larger volumes instead. The larger packs, called Extended Address Volumes, were introduced with z/OS 1.10 and support more than 65,280 cylinders. According to the documentation, the space in the first 65,280 cylinders is managed at the track level. The storage beyond 65,526 cylinders, labeled with the unfortunate name of Extended Address Space (EAS), is portioned out by the cylinder.
In z/OS 1.10, IBM limited support for the EAS to VSAM, but the new release extends the support to non-VSAM datasets. Z/OS 1.11 also allows dataset extents to span between track managed space and EAS.
The z/OS statements of direction
At the bottom of the preview letter are three statements of direction. The most intriguing outlines IBM's intention to provide a z/OS management facility as a separate product that will simplify administration and day-to-day operation of the mainframe system. Initially the product will manage problem management data and reporting for new or less-skilled systems programmers.
One of the other announcements has to do with issuing messages for STP hardware events. The other reiterates that BIND 9.0.0 functionality will be removed.
IEFBR14, which hasn't seen many changes over the years, will be improved with z/OS 1.11. In the new release, if you use IEFBR14 to delete a migrated dataset through JCL, the system will send an HDELETE command to HSM to remove the file instead of waiting for a recall to complete.
Miscellaneous new z/OS functions
This being an odd-numbered release, there is a ponderous list of miscellaneous new functionality that will be important for some and a big yawn for others.
- DFSMS support for solid-state devices in IBM DS8000 storage units.
- Extension of predictive failure analysis beyond the Common System Area monitoring added to z/OS 1.10. The preview letter didn't contain any more details but did use the word "heuristically" several times.
- A new spreadsheet application for post-processing Resource Management Facility data.
- HiperDispatch will now attempt to conserve cache and improve performance for zIIP engines as well as CPs.
- There are a couple of enhancements to how Sysplex Distributor (SD) metes out work. In z/OS 1.11 it will be able to take specialty engines into consideration. There will also be an attempt for SD to make better routing decisions, although details are still lacking.
- An option to tell RACF to restrict recording of user logon statistics to once per day. This is useful to enterprises experiencing high I/O and enqueue rates on their RACF database due to applications that perform logon ID and password validations with every message.
- Improvements to message flood automation to eliminate the requirement for coding user exits.
- Common Information Model server processing on the zIIP specialty processor engine.
ABOUT THE AUTHOR: For 24 years, Robert Crawford has worked off and on as a CICS systems programmer. He is experienced in debugging and tuning applications and has written in COBOL, Assembler and C++ using VSAM, DLI and DB2.
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This was first published in August 2009