1. Java URL Correction
2. New Enclave APAR
3. Cheryl Watson’s TUNING Letter 2001, No. 2

1. Java URL Correction

Andreas Steinberg noted that our link to the Java DeveloperWorks URL mentioned on page 28 is no longer active. You should use: http://www.ibm.com/developerworks/java.

2. New Enclave APAR

Greg Dyck of IBM’s z/OS Core Technology Design team points out the following: “APAR OW49428 (open) was just created to correct invalid counts for ASCBTCBS and ASCBTCBE in address spaces that use TCB in Enclaves… usually, but not limited to, the DB2 SPAS space. There is no identified performance impact, but given the experience of OW44517 there may be some. I thought people might be interested in it. This has existed since the introduction of TCB in Enclaves support in OS/390 1.3.”

3. Cheryl Watson’s TUNING Letter 2001, No. 2

The forty-four page 2001, No. 2 TUNING Letter was emailed to electronic subscribers on Friday, June 1. The print issues will probably be mailed out on June 11th. Here are a few of the topics we covered. You can purchase a printed copy of the current TUNING Letter for $85.

OS/390 R10 or z/OS R1?
The most common question I hear these days is whether to install OS/390 R10 or z/OS R1. Because of the potential changes and requirements when z/OS runs on a z900, this decision isn’t an easy one to make. z/OS running on a z900 requires two things: that you run in 64-bit mode and that you implement IBM’s new software pricing, Workload License Charges. Running in 64-bit real mode could provide a performance boost or pain; the new software pricing could cut your software costs drastically or increase them within the next two years. I discuss the pros and cons of R10 versus z/OS R1 decision in my Q&A on page 31.

A Small Mainframe
IBM has announced support for OS/390 (and z/OS soon) running on an Intel-based machine. Theoretically, this can provide from 10 MIPS to 45 MIPS. This is quite exciting news for several reasons: 1) it provides a path for the small MVS-based machines, such as the 4381s, 9xxx series, and other older machines; 2) it provides an inexpensive platform to run expensive old software (e.g. move your one VM application to a PC instead of paying for the full capacity of a larger S/390 or z900 machine; 3) it provides a very inexpensive development platform for ISVs to continue to develop products for the MVS platform; and 4) it can provide an inexpensive training environment for your installation. See our description of this new offering on page 22.

Our MIPS Ratings
The MIPS in our CPU Chart do not necessarily match those of other analysts. I’ve discussed this before, but the question keeps coming up. My Q&A on page 35 provides a further explanation of how why we might vary.

Elsewhere in this Issue
In our News section on page 4, we cover a Red Alert about GRS Star, several performance APARs (many of which are HIPER), tuning tips for CA-MIM, a note about CA-PMO and PDSE support, WebSphere pointers, some interesting problems reported on the forums, WSC Flashes and presentations, and new books and manuals. Which CICS level should you be running (and why) is answered by Bob Yelavich in our CICS Performance Tips on page 19. Java is the next language you should be learning. Find out why on page 23. Notes about R10 overhead, whether you need to reorganize your ICF catalogs, the difference between shared memory and shared storage (from Peter Enrico), and ways to use our TUNING Letter can all be found in our Q&A starting on page 34. While most sites are very happy with their z900s, several, by using our BoxScore software, have revealed problems with legacy COBOL programs. See the BoxScore results on page 29.

Stay tuned!