Commands applicable to online change

To perform a local online change operation, use the /MODIFY PREPARE, /DISPLAY MODIFY, and /MODIFY COMMIT type-1 IMS™ commands.

You can also perform a local online change operation using type-2 IMS commands if you set up your IMS as a single-IMS IMSplex with a minimal Common Service Layer (CSL) consisting of a Structured Call Interface (SCI), an Operations Manager (OM), and no Resource Manager (RM). This IMS configuration is called the enhanced command environment. For information about defining your IMS with a minimal CSL (no RM), see IMS Version 13 System Definition. For information about performing a global online change operation for a single-IMS IMSplex (including performing an ACB library member online change), see Overview of the global online change function.

When you perform an online change, you make the inactive libraries (those containing the changes to be made) active, or copy members from the staging library to the active library. Use the following commands in the following sequence:

1. /MODIFY PREPARE

   Use the /MODIFY PREPARE command to prepare an IMS for local online change and specify which resources to add, change, or delete. When you issue this command, IMS prevents terminals from queuing messages to database programs or transactions that will be changed or deleted.

   You might have to issue additional commands after /MODIFY PREPARE to display and resolve work in progress that might cause the commit to fail.

2. /DISPLAY MODIFY

   Use the /DISPLAY MODIFY command to produce a list of the resources (that are to be changed or deleted) that have work pending. No changes are accepted when work is pending. Use this command to ensure no work is pending before issuing a /MODIFY COMMIT command.

3. /MODIFY COMMIT

   Use the /MODIFY COMMIT command to apply the changes specified in a preceding /MODIFY PREPARE command. When this command completes successfully, modifications persist across all IMS restarts.

If a /MODIFY PREPARE or a /MODIFY COMMIT command is unsuccessful and you do not want to retry the online change until another time, use the /MODIFY ABORT command to abort local online change on an IMS and reset the status to what it was before you issued the preceding /MODIFY PREPARE or /MODIFY COMMIT command.