Why BCS?
Proven Services




1. If youíre running any level of OS/390 except OS/390 V2.10, youíre running an operating system that is no longer supported by IBM. This means if you have any problems with OS/390, IBM will charge you for support, and it may be difficult to find someone with expertise on your release. OS/390 V2.10 will be supported until at least 9/30/2004. For all availability and support dates, see http://www.ibm.com/

2. z/OS V1.4 is the last release to provide coexistence/fallback support for OS/390 V2.10, and thatís the only OS/390 release z/OS V1.4 provides this support for (one exception: OS/390 V2.9 running standalone). This means that if youíre still running a release of OS/390 below V2.10, you will very likely need to first upgrade to OS/390 V2.10, and then to z/OS V1.4, before you can upgrade to higher releases of z/OS. The lack of fallback support means you canít upgrade, then fall back to your old release with a guarantee it will still work. For a definitive explanation of IBMís fallback/coexistence policy, please, see z/OS V1R4 Planning for Installation, Chapter 5 - Ensuring Coexistence and Fallback, at http://publibfp.boulder.ibm.com/

3. When you decide to upgrade to z/OS, you DO NOT have to upgrade to z/Architecture (ARCHLVL 2) at the same time that you upgrade to z/OS. Starting with z/OS V1.4, IBM offers the Bimodal Migration Accommodation Offering, which allows you to first upgrade to z/OS, then within a 6 month time period, to convert your system(s) to z/Architecture. You must be running on a z/Series processor (z/800 or z/900) to implement z/Architecture. For more information on the z/OS Bimodal Migration Accommodation Offering, please visit

4. z/Architecture provides 64-bit addressing, and eliminates the need for Expanded Storage by providing the capability for an LPAR to use up to 64 gigabytes of Central Storage (as opposed to 2 gigabytes when running in ESA/390 mode). This can reduce paging and allows products like DB2 to exploit Data-In-Memory capabilities that can reduce I/O response time by making data immediately available to applications. Data-In-Memory techniques also can reduce the CPU time necessary to process channel programs. For more information on z/Architecture, please visit http://www.research.ibm.com/journal/rd/464/plambeck.html.

5. Speaking of performance, z/OS provides extensive enhancements in the area of dynamic tuning through the Intelligent Resource Director (IRD). IRD extends Workload Manager (WLM) goal mode processing to include the ability to react to changing workload requirements without human intervention, to be self-optimizing, to dynamically self-configure, and to enable autonomic computing. IRD also provides Dynamic Channel Path Management, LPAR CPU Management, Channel Subsystem Priority Queueing, and a variety of other real-time tuning capabilities. IRD requires that you run in z/Architecture mode. For more on IRD, please visit either 
or http://www-1.ibm.com/servers/eserver/zseries/zos/wlm/documents/ird/ird.html.

6. Not only are there performance reasons to migrate to z/OS, there are also cost reasons. z/OS introduced the concept of Workload Pricing. Workload Pricing means you pay for what you use, not for the size of processor youíre running (workload pricing requires that you run in z/Architecture mode). Shouldnít you pay for what you use? But you should also be forewarned: many Third Product vendors still charge based on the size of the processor, so you need to check with them, too. For more information on Workload License Pricing, please visit 

7. z/OS Managed System Infrastructure (msys) can greatly simplify and streamline system administration in a z/OS environment (as well as OS/390 V2.10). msys for Setup provides self-configuring, self-optimizing, self-healing, and self-protecting capabilities that make product configuration and customization easier and simpler. For more on msys for Setup, please visit http://www-1.ibm.com/

msys for Operations can simplify operations (especially in a Parallel Sysplex), and also provides self-healing capabilities for Couple data sets, the System Logger, and WTO buffers. msys for Operations improves both system and application availability by reducing operational complexity, improving awareness of system status and problems, and reducing operator errors. msys for Operations can be downloaded from the web. For more on msys for Operations, please visit 

8. msys exploits another advantage offered by z/OS called autonomic computing. Autonomic computing greatly advances the notion of self-managing systems, and has its roots in IBMís Project eLiza. Not only is autonomic computing provided on the z/OS mainframe server platform, it also runs on UNIX, midrange, and Intel server platforms. Autonomic computing is an enabler of dynamic e-business processing. For more on autonomic computing, please visit 

9. z/OS also provides a number of key enhancements in the area of IP networking and security. HiperSockets is a high-performance, highly secure mechanism for inter-partition communications, and significantly simplifies the network configuration involved. For more on HiperSockets, see 

Secure Sockets Layer performance compares favorably with other processing platforms and provides comprehensive cryptography support. z/OS has also been expanded to support Digital Certificate management (a.k.a. PKI Services). For more on IP security, see http://www-1.ibm.com/

IPv6 protocols expand the possible number of network addresses to 340 billion billion billion billion, simplify configuration and administration, and expand security capabilities. IPv6 requires a z/Series processor, using an OSA-Express adapter running in QDIO mode and when the zSeries is at driver level 3G (GA3 code) or above. For more on Ipv6, see http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/F1A1F100/CCONTENTS.

For more on z/OS network capabilities in general, see http://www-1.ibm.com/
and http://docs.share.org/proceedings/sh100/s3404.pdf.

10. z/OS also provides extensive application flexibility and expandability. Of course, z/OS still provides robust support for legacy COBOL applications using Language Environment under CICS, DB2, and IMS, plus Assembler has been expanded to provide 64-bit addressing capability. But z/OS also provides the same robust support for such "new world" application capabilities as Java (including Java Beans and Java SDK V1.3/4), and most significantly, XML. C++ is supported at the ISO í98 level, the Simple Network Time Protocol is now in z/OS, Unicode is now supported, as are CORBA business objects. UNIX file performance has been significantly improved, as have Websphere tuning capabilities. For more on the application capabilities that z/OS provides, please see 

11. IBM has developed a number of deliverables to simplify and streamline migration to z/OS. A key feature in this area is that IBM changed its release interval from 6 months to a year while maintaining its policy of providing support for 3 years after a release becomes available. IBM also intends to align its coexistence/migration/fallback support with that service policy (starting with the release after z/OS V1.5 in 9/2004). This halves the number of releases you have to cope with while simplifying migration planning and scheduling. As part of a phaseover period, z/OS V1.5 will be available in 3/2004, and the first annual release will be available in 9/2004. For more information on this policy change, see the Statement of Direction and Service Policy sections of http://www.ibmlink.ibm.com/usalets&parms=H_202-190.

IBM has also produced a z/OS V1.4 Migration Ė From OS/390 V2.10 to z/OS V1.4 manual (at http://publibfp.boulder.ibm.com/
) that consolidates the information from the many Migration Guides that existed for OS/390 components, plus more. This document works with the z/OS V1R4 and z/OS.e V1R4 Installation Planning Wizard 
(at http://www-1.ibm.com/servers/eserver/zseries/zos/wizards/ipw/ipwv1r4). These facilities greatly simplify the planning phase of a migration. For a list of all the z/OS Wizards, see http://www-1.ibm.com/servers/eserver/zseries/zos/wizards.

Taking this concept a step further, the z/OS Migration Starter Kit, from Best Customer Solutions, Inc., incorporates the information in the above manual/wizard into a Microsoft Project plan. This plan includes most z/OS and ServerPac migration and installation tasks, and couples these tasks with hundreds of hyperlinks to information across the Internet. These hyperlinks connect not just to relevant IBM and Third Party manuals, but also presentations and White Papers by SHARE, IBM, and other vendors and consulting firms to provide technical guidance at the click of a mouse. For more information on the z/OS Migration Starter Kit, see http://www.mainframehelp.com/upgrade_plan_templates.htm.

12. Are there more reasons to migrate to z/OS? Literally dozens! Perhaps not to the degree of the reasons listed above, but depending on your configuration and the nature of your applications, other new z/OS functions may be key to your operation. This includes z/OS.e, which provides a unique, powerful platform for running e-business applications on the z/800, and the capability to develop and run legacy, UNIX, and LINUX systems in parallel, all communicating and sharing data within a common environment. Take some time to go to the z/OS Home Page, at 
, and browse through some of the pages. Youíll be impressed with what you find.



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Last modified: 06/13/2006