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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.