IBM Operating System Upgrade Successful
By Nick Zaharchuk, OIT
The State of Maine Office of Information Technology Mainframe Support Team (Ann Salverson-Seales and Nick Zaharchuk) successfully upgraded the State IBM mainframe computer operating system on Sunday, December 6, 2009. The planning, installation, customization, upgrading of third-party products as required, and testing have been in the works for more than a year. The purpose of the upgrade was to maintain a vendor-supported application hosting environment for the State of Maine 's IBM Enterprise Server-based applications.
To facilitate the installation, customization, third-party product, and application testing process, both the prior production and new operating system releases were configured to run concurrently on the same IBM Enterprise Server. While each operating system image ran independent of the other, they did share access to all application disk and tape-resident data. This methodology provided an excellent environment for the customization and pre-production testing of the many third-party software products and State of Maine agency applications. As certain system resources were not sharable between the two levels of the operating system, a series of Sunday test periods were scheduled to allow for pre-production testing of those resources. The DB2 relational database management subsystems, job scheduler, and access to the COLD (Computer Output to Laser Disk) system are not sharable resources. In the case of the Sunday test periods, which were scheduled in November of 2009, the new operating system was brought up in place of the prior operating system for the afternoon. Upon conclusion of a Sunday test period, the system would be re-IPLed (rebooted in PC terminology) to its prior operating system release level. This not only allowed for a more comprehensive testing of applications but also provided OIT staff the opportunity to document, verify, and refine the steps required to migrate to, and fallback from, the new operating system release.
The current practice of the IBM Corporation is to provide its customers a new operating system release on an annual basis, and guarantee migration compatibility and fallback support within three consecutive release levels. This allows customers to skip an annual release level, if they so choose. In the case of the State of Maine , OIT staff upgraded the z/OS operating system from Version 1 Release 7 to Version 1 Release 9. Version 1 Release 11 was made available to customers on September 25, 2009 and is the next release upgrade planned for the State of Maine 's IBM Enterprise Server.