Rational Developer for System z
Enterprise COBOL for z/OS, Version 4.1, Compiler and Runtime Migration Guide


STEPLIB example

Here is one example of how to phase in Language Environment using the STEPLIB method: for an organization that has a central development center (all compiling and linking is done in one location) and separate production sites. This is a very conservative approach, but it has been used by many customers who require absolutely no disruption in production applications.

  1. Certify Language Environment and Enterprise COBOL at the central development center.
    • Run tests with captured data on your current run time, and save all results.
    • Install Language Environment in a STEPLIB environment. This means that unchanged jobs will run with your current run time, and that some users can use the Language Environment run time by using STEPLIB JCL to access the Language Environment runtime library.

      Note for NORES applications: This section does not apply to NORES applications that have not been changed. However, if you change your NORES applications (for example, by link-editing them with Language Environment), they might behave differently than before the link-edit.

    • Run tests with captured data on the Language Environment run time, using the STEPLIB environment, and compare the results to your current run time. Run parallel tests throughout the certification cycle to ensure that your applications produce the same results when run with Language Environment as they did with your current run time.
    • Finally, compile your test applications using Enterprise COBOL. STEPLIB to the Language Environment runtime library, and rerun the certification tests.
  2. Install Language Environment on the central development center's system and test.
    • Run parallel tests of the nonconverted versions of your existing applications using STEPLIB to access your current run time.
    • Run all new applications in the Language Environment runtime environment before releasing to production.
  3. Prepare a backout strategy
    • Save the procedures for installing your current run time in case you need to back out the Language Environment run time.
  4. Install the Language Environment run time at one production site.
    • Continue to run parallel tests of the nonconverted versions of your existing applications with your current run time in the STEPLIB environment.
    • Run the Language Environment run time for one month at this production site.
  5. Install the Language Environment run time at all production sites.
    • Optional: continue to run parallel tests of the nonconverted versions of your existing applications with your current run time in the STEPLIB environment.
    • Run the Language Environment run time for one month at all production sites.
    • After one month, delete the entire contents of your current runtime library.
  6. Compile all new or changed applications with Enterprise COBOL.

Try to move the largest units of work that you can. Moving entire online regions, applications, or run units at once ensures that interactions between programs within an application or run unit can be tested.


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