Application Migration Considerations › Application Migration Considerations › Replacing Online Applications

Replacing Online Applications

The basic requirement of any online line application system is the ability to install new application software or replace existing applications with updated software while the online line environment is running. These steps differ slightly based on whether you are running VLS or load module format.

Using load module/phase format:

1. Migrate the application using one of several methods resulting in load modules available to the production environment.
2. Use the DISABLE RUN command to force active users off the affected application and suppress potential users from gaining access while you are installing the application.
3. REFRESH the load modules.
4. Use the ENABLE RUN command to allow users to start running their applications again.

With load modules, you can execute Step 1 only and wait until CICS is recycled to bring in the new versions of the application programs.

Using VLS format:

1. Use the DISABLE RUN command to force active users off the affected application and suppress potential users from gaining access while you are installing the application.
2. Transport the application using the object transport utility.
3. Use the ENABLE RUN command to allow users to start running their applications again.

If there is a mixture of load modules and VLS format for a single application, it is still necessary to execute the object transport utility for VLS run programs between the DISABLE and ENABLE of the application and panels in VLS format.