IBM Previews z/VSE V4.2, Releases DB2 Server V7.5
Published: November 27, 2007
by Timothy Prickett Morgan
The bits are barely cool on z/VSE V4.1, which started shipping in March after a January launch this year, and IBM is already putting out a technology preview of its VSE V4.2 operating system. In general, technology previews mean Big Blue is getting ready to ship a product in six to nine months, but it is always helpful to remember that such timing is a general guide, not a hard and fast rule.
In this case, IBM appears to be talking up the future operating system because it will not come to market until the fourth quarter of 2008. With mainframe sales on the skids in the third quarter and likely to be down until a new line of servers based on the z6 processor comes to market in 2008, IBM is going to open up its roadmaps and get customers and their budgets lined up for sales as soon as it can in 2008. There's no word from IBM--yet--as to when we can expect z6 machines, but you can bet that IBM is working feverishly to get the new machines out the door.
z/VSE 4.2 breaks a number of long-standing barriers for the VSE/ESA platform. First, it quadruples the amount of main memory that processors can address, up to 32 GB. This might not seem like a big deal for big RISC/Unix boxes that span up to 1 TB or 2 TB of main memory, but it is a lot of memory for an architecture that is four decades old and for the relatively skinny (and efficient) green-screen and database applications that reside on mid-frame boxes out there in the world.
z/VSE 4.2 will also support more than 255 concurrent VSE tasks; IBM is not saying how high the ceiling will be, but the net result will be that z/VSE can now scale as well as the underlying dual-core z9 and quad-core z6 processors inherently allows. (The ratio between VSE tasks and processor instruction threads is not one-to-one, of course. But clearly customers want to be able to use more than 255 tasks on a relatively big box so they can get it to do more work.)
IBM is raising the VSE tasks ceiling primarily to boost the performance of CICS/COBOL applications, and with good reason. z/VSE V4.2 will be the last release of the VSE platform to support CICS/VSE. In future releases of VSE, IBM will require customers to use the more modern--and more resource intensive--CICS Transaction Server for VSE/ESA. IBM has been bundling a copy of CICS/VSE with CICS TS for free and will continue to do this with z/VSE V4.2. The implication in that statement from Big Blue is that after V4.2, it will no longer do this. And the fact that IBM is telling customers it is raising the VSE tasks ceiling above 255 tasks to help with the transition to CICS TS means that some of the extra overhead is being provided solely to help customers make that transition. Whether or not customers actually do this is another matter. It is perfectly plausible that IBM creates an artificial barrier at V4.2 with this practice, giving customers the ability to execute more CICS transactions on V4.2 compared to V4.1 or earlier VSE releases while allowing them to keep using the older CICS/VSE transaction monitor.
IBM is also talking up the affinity between VSE and Linux workloads for z/VSE V4.2, but the exact nature of the improvements IBM is making (beyond the ability to partition a mainframe to run VSE and Linux side-by-side) are not clear. The idea is to allow applications running on z/Linux partitions to communicate with databases and applications residing on z/VSE. IBM is citing Linux as the mainframe operating system for WebSphere middleware, Domino groupware, new Linux-based ERP software and DB2 databases, infrastructure workloads (print, file, and Web serving), and application development and test environments.
z/VSE V4.2 will run on zSeries 800, 890, 900, and 990 servers as well as on System z9 Enterprise Class and Business Class servers; it only operates in z/Architecture mode--meaning 64-bit real mode--for the operating system. z/VSE V4.2 does not support 64-bit virtual addressing for the operating system or 64-bit addressing for applications running atop the operating system. At some point--when customers need more memory for applications--IBM will have to rise above 24-bit and 31-bit addressing for user applications. z/VSE V3.1 is, of course, the last release of VSE to run on 31-bit System/390 and zSeries iron.
In a related announcement, IBM will this week begin shipping its DB2 Server V7.5 database for VSE and VM mainframe operating systems. This variant of the DB2 database is a derivative flagship mainframe relational database from IBM that was created for MVS and updated for OS/390 and z/OS; it is, like all mainframe variants of the DB2 products, distinct from the DB2 Universal Data Base product for Windows, Unix, and Linux servers and the integrated database inside of OS/400 and i5/OS midrange platforms, commonly called DB2/400.
With DB2 V7.5 for VSE and VM, customers will be able to build two-tier and three-tier database applications--the first time this capability has been available with DB2 with these two mainframe operating systems. The software also includes a client that allows applications to link to other DB2 databases and link with CICS and other applications running on VSE and VM platforms. In the past, if customers wanted this DRDA connectivity, they had to buy a full DB2 license for these machines, even if they were not really storing data, but just accessing it on another platform. DB2 V7.5 for VSE and VM can link to DB2 UDB V8.1 databases on Windows, Unix, and Linux platforms using ODBC and JDBC protocols, but oddly enough cannot connect to earlier DB2 UDB releases and versions. DB2 Server V7.5 is supported on z/VSE V3.1 or higher and z/VM V5.2 or higher.
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