In-Depth

OS/390 Migration: An End Run Around Y2K

• 12/01/1999

Recently, the trade press has given substantial attention to Y2K concerns and how they have led some companies to re-host their mission-critical mainframe-based applications onto client/server platforms. The number of companies that have opted for this strategy is dwarfed by a far greater number of firms who have stayed with mainframe platforms, but have been forced to migrate from Y2K-questionable MVS to Y2K-compliant OS/390. (According to IBM, both OS/390 Version 2 Release 7 and MVS Version 5 are Y2K-ready with the application of a code patch from, or the performance of other services by, the vendor.)

Migrating between mainframe operating systems is always a challenge. For IT organizations driven to the task by new application requirements combined with Y2K concerns, migration can seem more like a forced march. Fortunately, many companies have found the road a bit easier to travel, thanks to products that preserve their investment in older, hand-coded JCL and program exits.

On October 10, 1995, IBM unveiled the OS/390 mainframe operating system with the bright-eyed enthusiasm of a new parent. OS/390 was described in the announcement letter sent by the vendor to customers, integrators, analysts and trade press editors as "MVS transformed into a leading-edge server operating system, delivering a modern set of server functions." The new operating system featured enhanced support for open systems networking, reduced complexity through the integration of functions previously distributed as 25 separate products in the MVS environment, and support for client/server application architectures. It signaled a desire by the centralized computing camp to make peace with the decentralized computing camp and to become another server in the open systems network.

The marketing program surrounding the announcement included the posting of photographs and sound bites from several prominent customers and business partners to IBM’s Web page endorsing the new product. The future seemed bright, and migration of IBM’s mainframe customer base from MVS to the new operating system was a given.

However, not everyone was convinced that a business case existed for migrating to OS/390. The enhanced features of the new operating system could not budge companies that had little use for these capabilities or that had made significant investments in customizing their MVS environments.

Three years later, when IBM announced OS/390 Version 2, Release 7, many "MVS holdouts" persisted. The explanation offered by some observers, that these companies simply did not understand the advantages of the new-and-improved OS, seemed less than plausible. It seemed more likely that many IT organizations lacked the time, resources or staff competence to perform the migration.

In other cases, failure to migrate came down to an "ornery" IT decision maker, who took exception to migrating away from MVS as a matter of principle: "If it isn’t broken, why change it?" These managers pointed to their warranty agreements with IBM, which committed the vendor to support MVS (Version 5) through the year 2000.

The story might have ended there, with a minority of MVS users refusing to follow the migration path set forth by IBM. However, business requirements have a way of changing even the most reasoned plans of corporate IT managers. At the data center of the City and County of San Francisco, for example, mounting concerns over Y2K, combined with pressures to deliver new system support for various government departments, changed migration from an option to a priority. An eight-person mainframe support staff, which had barely recovered from a 1996 MVS/XA to MVS/ESA migration effort, received the word in late 1997 that they were about to migrate their applications once again – to OS/390.

"We were several [MVS release] levels behind," admits Stimson Lowe, Manager of Technical Support in San Francisco’s Department of Telecommunication and Information Services, noting that any migration entailed substantial effort and risk due to the organization’s customization of their operating system environment.

"We had many customized system exits on two separate mainframes," Lowe recalls. "Now, we needed to consolidate both mainframes onto a single 9672 with an OS/390 operating system. That was partly for Y2K [compliance], but mainly to meet deadlines for providing other services to our customers, which represent all city functions, except for education and utilities."

According to Lowe, the Department of Telecommunication and Information Services provides multiple systems to more than 2,500 end users. These include a court management system for the judiciary, resource management, accounting, standards and statistics for City Hall, and a 911 emergency calling system for the police department. Any activity affecting these systems had to be accomplished within very strict timeframes and with little margin for error. Migration was not an undertaking to be treated lightly.

"We figured that doing the upgrade would take an enormous amount of system programming time. Our MVS environment had many customized system exits that would need to be completely rewritten for a new environment. At the same time, we had promised the police department that their new 911 system would be in place by a certain time. That date required the move to OS/390 be made soon."

Fortunately, says Lowe, the Department had acquired Operating System/Environment Manager (OS/EM) from Trident Services (Sausalito, Calif.) when the firm had assisted the department in its XA to ESA conversion. The product enabled the organization to eliminate exit mods altogether by reassigning those functions to OS/EM. "Based on our previous experience with the product, we knew it would save us three months of system programming time, at least," explains Lowe.

OS/EM replaces all IBM-supplied JES2, JES3, RACF, DFHSM, TSO/E, SMF, DFP, ALLOCATION and ISPF Installation Wide exits with its own control processor, which is installed at IPL time. The OS/EM control processor dynamically loads and processes exits, whether they are user-written or program-generated. All of OS/EM’s features are invoked and driven by a series of ISPF menus designed for ease-of-use by operations and management personnel, with a minimum of support from the systems programming staff.

Leveraging the capabilities of OS/EM as well as support from Trident Services, Lowe says that the consolidation and migration project went smoothly. "We created four logical partitions (LPARs), including one for testing and another for Y2K-specific testing. We would not have made it by our projected date without OS/EM."

Says Lowe, the value of the OS/EM tool suite did not end with the migration. OS/EM also enabled the Department to simplify its environment by eliminating third party data mover software and to standardize on IBM’s own hierarchical storage management (HSM) platform, used for moving selected data and directories from DASD to tape.

OS/EM includes an HSM Optimizer with easy-to-use controls that can improve performance in the DFSMS storage environment. With the tool, usable storage is maximized and processing overhead is minimized by eliminating unnecessary migration processing.

In addition, Lowe says, OS/EM enabled the department to set up policies governing system resources "that allowed us to prevent some programmers from making huge virtual storage regions that caused memory paging problems." Moreover, by enabling the setup of job classes and providing the means to track department and project codes associated with specific job cards, OS/EM enabled the Department to implement a job accounting and charge-back system.

While Lowe does not claim that operating system migrations have become a favored pastime, he does emphasize that many of the difficulties that might have accompanied the MVS to OS/390 migration at the City and County of San Francisco were avoided through the use of the OS/EM suite of tools. That view is shared by Jerry Whitteridge, an MVS Systems Programmer with Safeway’s System Technology Department (Walnut Creek, Calif.).

Safeway Inc. is one of the world’s largest food retailers, operating more than 1,500 stores in the United States and Canada. According to Whitteridge, the System Technology Department provides services to more than 5,000 end users throughout the Safeway organization.

Whitteridge illustrates the mission-critical role of IT infrastructure by describing an order process, "Our stores have their own processing capability. They transmit orders and financial information to our corporate mainframes, which, in turn, communicate orders to Tandem systems that host our warehouse application. That warehouse system processes the orders and directs requisitions to our warehouses that are used to load trucks. The trucks then deliver products to the stores."

Supporting these and many other key applications requires mainframe processing power. Prior to 1997, the company was running multiple mainframes with different versions of MVS. They were interested in migrating the systems to a single OS/390 platform running multiple LPARs, but "some of the systems were very customized. We figured we were looking at three to four years to upgrade, because of the man hours that would be required to implement standard exit points for the systems before we migrated to a vanilla environment. We had really customized [the Job Entry System]. There were a lot of hooks in the system and we all wanted to get away from them."

At last, says Whitteridge, the financial benefits expected from the consolidation of data center operations gave Safeway the nudge to OS/390. "We decided to do the project as a series of consolidations over time. We were going to consolidate MVS systems onto a four LPAR mainframe, then stabilize the applications and upgrade the exit points. Then, we were going to migrate to OS/390 Release 1, and finally to OS/390 Release 1.3."

Fortuitously, Whitteridge says, Trident Services was contacted to discuss ways to handle exit upgrades. The vendor suggested that Safeway deploy OS/EM in order to eliminate the man hour allocations required for exit upgrades from the project plan. Using OS/EM, no user exits were required, since the product provided the functions required by the applications running on the mainframe. Safeway deployed the product shortly thereafter.

Within three months, the project was already ahead of schedule. OS/390 was deployed in a development environment and work was proceeding on the upgrade of programs. Following a brief delay, during which Safeway acquired the assets of a small grocery store chain and also relocated its own data center, OS/390 Release 1 was moved into a production LPAR in October 1997.

Commencing in April 1998, Safeway prepared for a second OS/390 migration. First, the operating system was deployed into a development LPAR (so that applications could be tested and integrated). By July 1998, the new operating system went into production, with three LPARs in a production sysplex, two in a development sysplex and one in a Y2K testing sysplex.

Whitteridge says that the success of the three migrations provided the company with an application environment that has become a standard mark for Safeway. With OS/EM, the company realized a three-to-four-year time savings across multiple migrations. He reports that the company, now confident in its ability to manage migrations effectively, is using the same methods to transition to Release 2 – an effort he expects to conclude this year.

Confidence is the key ingredient of success at Total System Services (TSYS, Columbus, Ga.). According to Systems Programmer, James Lusk, TSYS is one of the world’s leading information technology processors of data transactions and payments for domestic and international users of credit, debit, commercial and private-label cards. The company offers clients a range of services that include online accounting, data processing, electronic commerce services, portfolio management, account acquisition, credit evaluation, risk management and customer service.

Remaining competitive means staying current with technology. According to Lusk, TSYS operates 16 mainframes, a combination of IBM and Hitachi Data Systems mainframes. Since 1997, the company has been migrating all of the operating systems from MVS 5.1 to OS/390 to meet customer requirements and to ensure Y2K compliance of its systems and applications.

Says Lusk, "We knew about OS/EM’s exit handling capabilities and trialed the product in 1997. At the time, we had [an accounting code exit] in one of our MVS systems that we wanted to replace. Trident Services had a pre-written exit in their OS/EM product that enabled us to use ISPF panels to set up the same function on the fly."

Lusk reports that the product was very easy to install, "We installed it in two hours and we were using it in five hours. It was simple to learn, all of the training was on-the-job. We immediately saw that it was a great timesaver. Fixing an exit mod didn’t require an assembler programmer; a junior systems programmer could do the work."

The trial turned into a purchase once TSYS discovered the power of the product, which, Lusk says, "went beyond basic exit support."

"OS/EM provides extended options and parameters that enable us to do loads and restrict exits based on jobs. It is good for testing applications."

He reports that the product is now used in migrations, Y2K compliance testing and application program testing prior to migration, "The cost benefit argument was made as soon as we looked at what it would cost to do the work without OS/EM."

About the Author: Jon William Toigo is an independent writer and consultant specializing in business automation solutions. He can be reached via e-mail at jtoigo@intnet.net, or through his Web site at www.toigoproductions.com.