The VSE Operating System State of the Union B y J o h n L a w so n

BM has made several announce- What follows is a brief review of some took 6K and the remaining storage was ments in recent years that affect of those events which have preceded available for program execution. When I which versions of the VSE operating similar events that occurred this year. compared to today’s most current ver- system are still available to customers As many of us know, it all began in sion, z/VSE 4.1, with a supervisor of and which versions are still supported 1965 when IBM announced revolution- about 700K and support for up to 8GB for service. This article reviews these ary System/360 (S/360) processors and of real storage, VSE users can definitely announcements and their implications along with that announcement, an oper- see how much their operating system for the hardware platforms on which ating system to run on the smaller mod- has evolved and grown to support much customers are still running VSE. els of those processors. This new larger systems than originally intended. operating system was named Disk Each major name change in the VSE VSE History: A Hardware and Operating Operating System/360 (DOS/360), or as operating system was usually related to System Evolution it was more commonly called, DOS (not support of new processors or operating What we know today as the VSE to be confused with the PC operating system capability. The announcement of operating system began more than 40 system by the same name that came a new version or release of VSE often years ago. Throughout its history, VSE along much later). There are a few of us included discontinuance of support for customers have had to make both hard- with gray hair still around who remem- older technology processors. In 1972, ware and operating system upgrades to ber installing DOS on 24K and 32K IBM announced System/370 processors take advantage of new technologies. S/360 systems. The DOS supervisor and virtual storage. DOS/VS was

z/Journal • October/November 2 0 0 7 announced to support that new proces- these systems had to eventually upgrade 2000 models and the P/390, R/390, and sor family and its virtual storage capa- to new processors to remain on a sup- S/390 Integrated Server. VSE/ESA 2.7 bilities, and customers experienced their ported VSE version. dropped support for these and provided first upgrades of hardware and operat- VSE/ESA Version 2.4 was announced support for the new zSeries systems, the ing systems to exploit new technologies. in 1998 and supported ESA/390 mode Multiprise 3000, the 9672 G5 and G6 In 1979, IBM announced the 4300 only. This included support for all the processors, and equivalent systems that family of processors. DOS/VS was 9672 processors, ESA/390-capable included the FLEX/ES solution men- replaced by an “extended” version, ES9000 models, and the Multiprise 2000 tioned earlier. DOS/VSE, to support these processors processors, which were succeeded by VSE/ESA caught up with the rest of and to provide exploitation of the larg- the Multiprise 3000 the following year. the “z” operating systems from a naming er, real memory sizes of these systems VSE/ESA Version 2.4 dropped support standpoint when it was changed to z/VSE with more partitions and virtual stor- for ESA/370 mode, so ESA/370 mode in the z/VSE Version 3.1 preview age capabilities. The processor and processors, such as the ES/3090 E/J/S announcement in April 2004. With its VSE operating system evolution con- models and ESA/370 mode 4381 mod- general availability in March 2005, tinued in 1986 with the announcement els, were no longer supported and cus- z/VSE 3.1 supported the same processors of the 9370 line of processors and tomers with those processors had to and new processor functions as VSE/ESA VSE/Systems Package (VSE/SP). In the upgrade to ESA/390-capable systems to 2.7 and added support for SCSI drives early ’80s, S/370-XA (eXtended stay on current VSE releases. attached to zSeries FCP channels. Architecture) was announced. This VSE/ESA also was supported on IBM’s latest mainframe processor provided 31-bit support capabilities some new entry-level systems that were technology, System z9, was announced for MVS and VM systems; however, introduced during this timeframe to later in 2005. Even though VSE/ESA 2.6 VSE/SP supported only S/370 24-bit replace smaller 4300 and 9370 systems. and 2.7 as well as z/VSE 3.1 supported (16MB) architecture. These were the PC Server 390 (P/390), zSeries and z9 processors, they didn’t In 1990, VSE/SP became VSE/ESA. R/390, and S/390 Integrated Server, support 64-bit architecture and ran only This was the first VSE release to support which gave those customers who were in 31-bit mode (2GB real and virtual Extended System Architecture/390 still running on the older hardware with addressing) on these systems. This (ESA/390) and System/390 processors unsupported VSE releases an economi- brings us to 2007 and the announce- such as the 9021, 9121, and 9221 proces- cal solution to upgrade their hardware ments and events this year that have sors introduced with the ES/9000 proces- and VSE software to supported levels. changed the state of VSE/ESA and sor family. VSE was extended to support Many of these were later replaced by the z/VSE. 31-bit real and virtual addressing. VSE/ FLEX/ES solution from Fundamental ESA also still supported the ESA/370 Software, Inc. This solution enabled VSE Today mode and 370-mode of the earlier pro- emulation of S/390 architecture on Three important announcements cessors that VSE/SP Version 4 supported, Intel-based servers and provided anoth- and one event have occurred this year except for the System/370 135 and 138 er economical upgrade solution for that will have a significant impact on models. This new VSE version allowed smaller VSE customers. VSE service support and availability. customers to move to newer supported As the 21st century began, and First, z/VSE Version 4.1 was levels of the operating system without everyone breathed a sigh of relief that announced on Jan. 9, 2007, and became having to do a processor upgrade. the year 2000 started quietly except for generally available on March 16, 2007. In 1994, IBM announced CMOS tech- the usual fireworks and noise makers, This newest z/VSE version is the first nology with the first generation of the IBM continued the mainframe hard- to operate in z/Architecture mode only. S/390 Parallel Enterprise Server proces- ware evolution. IBM eServer zSeries z/VSE 4.1 supports 64-bit real addressing sor family or 9672. Several other genera- processors and 64-bit (z/Architecture) with exploitation of up to 8GB of real tions followed along with the Multiprise were announced, starting with the z900 memory but doesn’t provide support for 2000 processors for smaller users. Version and z800, and were followed by the z990 64-bit virtual addressing. z/VSE 4.1 is 2 of VSE/ESA was announced in support and z890 a few years later. New releases supported on zSeries and z9 processors of these new systems. The new turbo-dis- of VSE/ESA Version 2 also were only and doesn’t support the older tech- patcher in this version allowed VSE to announced, which exploited some of nology processors. Mid-range Workload support and exploit multi-processors. the functions of the new hardware. License Charges (MWLC) were Support for 370-mode processors was VSE/ESA 2.6 was the last release to announced for z/VSE 4.1 to provide VSE discontinued; thus, VSE/ESA V2 no lon- support some of the older technology users the opportunity to reduce their ger ran on 9370, 4341, 4361, or selected processors, namely, the 9672 G3, G4, software license charges when running z/ 4381 processor models so customers on R1, R2, and R3 models, the Multiprise VSE 4.1 on z9 processors. Second, the last of the VSE/ESA Withdrawal From Marketing Withdrawal From Service releases, Version 2.7, was withdrawn Announced E ective Announced E ective from service on Feb. 28, 2007. This z/VSE 3.1 6/05/2007 5/31/2008 8/07/2007 7/31/2009 leaves z/VSE 3.1 and z/VSE 4.1 as the VSE/ESA 2.7 6/07/2005 9/30/2005 8/02/2005 2/28/2007 only supported VSE operating system VSE/ESA 2.6 2/18/2003 3/14/2003 8/03/2004 3/31/2006 versions. All previous VSE/ESA releases VSE/ESA 2.5 12/14/2001 8/06/2002 12/31/2003 already have been withdrawn from ser- VSE/ESA 2.4 9/29/2000 3/06/2001 6/30/2002 vice in prior years. VSE/ESA 2.3 2/29/2000 6/30/2000 3/07/2000 12/31/2001 Third, on June 5, 2007, IBM announced plans to withdraw from Figure 1: Withdrawal From Marketing/Service Dates for z/VSE and VSE marketing z/VSE 3.1 effective May 31,

Sound Off! Comment on this article by visiting z/Journal • October/November 2 0 0 7 http://community.zjournal.com/zVSE. 2008. While a withdrawal from market- 3000 or 9672 G5 or G6 processors, an hardware technologies and new archi- ing means only that a specific version or upgrade to z/VSE 3.1 would move them tecture. As the VSE history review release of that product can no longer be to a level that would be supported until shows, there have been several such ordered after the effective withdrawal July 31, 2009; however, when that ver- transitions from S/360 architecture to date, what usually follows around that sion is withdrawn from service, they S/370, from S/370 architecture to effective withdrawal date is a withdraw- would need to upgrade to a zSeries or ESA/390, and now from ESA/390 to al of service announcement. z9 processor first before they could z/Architecture that require both proces- The last of the announcements, the upgrade to z/VSE 4.1. Customers using sor and operating system upgrades. As withdrawal from service for z/VSE 3.1, a FLEX/ES solution would need to do the little DOS system grew to take recently occurred on Aug. 7, 2007. The the same upgrades but there may be advantage of the new hardware tech- effective date for this withdrawal from licensing issues involved in moving to nologies, z/VSE 4.1 has continued the service is July 31, 2009. After this date, z/VSE 4.1. For more on this issue, see evolution by exploiting all it can of the z/VSE 4.1 will be the only release sup- “The State of IBM Mainframe z/Architecture technology. ported of those that are currently Emulation” by Phil Smith III in the For more on the history of VSE, see available today and users would need April/May 2007 issue of z/Journal. the history document on the IBM z/ to migrate to z/VSE 4.1 to be support- An upgrade to z9 with z/VSE 4.1 VSE Website at http://ibm.com/zseries/ ed. Customers on older unsupported may be the most economical because of zvse, which, along with my own expe- releases could still download PTFs for the MWLC and sub-capacity software riences, helped in the writing of this those releases if they are available, but licensing available with MWLC. Even article. Z they wouldn’t be able to get defect sup- though the hardware costs may be more, port on new problems without having they could be offset by the software About the Author a special fee-based extended service license cost savings available with John Lawson is a senior technical support contract from IBM in place. The table MWLC (see “MWLC for z/VSE 4.1: representative for illustro Systems International, LLC, in Figure 1 summarizes the dates from Can It Save You Software Costs?” by a VSE technology company that provides professional services to the VSE community. He has more than these and prior announcements for John Lawson in the April/May 2007 40 years of experience providing technical expertise VSE/ESA and z/VSE 3.1. issue of z/Journal). to CICS and VSE users in the areas of system design, For VSE customers with zSeries or Upgrading mainframe processors implementation, usage, education, performance z9 processors, this isn’t an issue, since has been part of the process necessary analysis, and capacity planning. z/VSE 4.1 supports those systems. For to stay on a current, supported version Email: [email protected] customers running VSE on Multiprise of VSE and to take advantage of new Website: www.illustro.com

z/Journal • October/November 2 0 0 7 • C o p y r i g h t © 2 0 0 7 z / J o u r n a l