To understand the key phases of a migration project, refer to:
- The IBM COBOL Migration Guide (GC27-1409-05)
- IBM PL/I Migration Guide (GC27-1458-05)
- IBM LE Run-Time Migration Guide (GA22-7565-07).
These resources identify almost all the possible migration issues that might arise. If you can determine which of the several hundred pages in each guide apply to your situation, an LE or compiler migration will no longer be a major technical challenge.
Remember, too, that migration is no longer a one-time activity. It will be an ongoing part of each new release of the operating system and each new compiler release. Keeping up is more important than ever and several small steps are easier than one large one.
It’s important to understand that what’s often referred to as an LE migration actually consists of two separate migrations—the run-time migration and the compiler migration(s). Each has two individual steps.
Before you start, you should understand the concepts, functions, and features LE provides. In this educational effort, you’ll see where the compilers and run-time fit into the process. The next phase involves assessment of the effort and planning the tasks to be performed. Both the run-time and compiler migrations require a comprehensive inventory of the languages and runtimes your applications use. The assessment is what you do with that inventory.
The run-time migration consists of two sub-steps: First, you start running with the new dynamic run-time library (SCEERUN). Then, once that’s stable, you start link-editing with the new runtime library static components (SCEELKED).
Once you have a stable run-time environment, you can begin compiler migration by re-compiling with the new LE-conforming compilers. It isn’t necessary to complete the entire run-time migration before starting the compiler migration. Once LE is stable for an application, the compiler migration can begin in parallel with the continuing migration of the run-times for unrelated applications.
What Tools Are Available?
At the SHARE User Group (www. share.org), almost all LE migration presentations recommend the use of automated tools whenever possible. Tools are usually written as repeatable processes that look for specific conditions or issues that are known troublemakers. The quality and maturity of the tool are important to your success. Many of the premier tools have been available for more than a decade and were battle tested during Y2K.
John Scull, an LE/compiler migration specialist with the IBM Global Services organization, is responsible for MVS Program Products support for IBM internal locations. His 2006 SHARE presentations, Session 8231, “An LE Migration From A to Z,” is a step-bystep approach to LE migration. His most recent SHARE presentation has the same session number, but is titled “DB2, CICS and IMS Are Moving On—Will Your Program Languages Keep Up?” This presentation addresses migrations as they apply to DB2 and CICS. All of his sessions are available to SHARE members on the SHARE Website. John believes in using the best automated tools available to perform assessments and to manage the progress of a migration. He will start an assessment project only when the customer has installed an appropriate set of LE migration tools.