Creating runtime resource and descriptor definitions

When dynamic resource definition (DRD) is enabled, you can define runtime resources and descriptor definitions to IMS dynamically, eliminating the requirement to use the online change process or to cold start IMS.

When a resource or descriptor is defined to IMS, IMS stores information about the resource or descriptor, such as the attributes and the status, in control blocks. The information that is kept in the control blocks is referred to as the runtime resource or descriptor definition. Although the overall process for creating runtime database, application program, transaction, routing code, MSC physical link, MSC logical link, MSC MSNAME, and MSC remote LTERM definitions is the same, there are minor variations in the steps you complete.

When DRD is enabled for MODBLKS resources, runtime resources can be created by:
  • Importing the stored resource definitions from the IMS.MODBLKS data set during an IMS cold start.
  • Importing the stored resource definitions from the resource definition data set (RDDS) with the automatic import function or the IMPORT DEFN SOURCE(RDDS) command.
  • Importing the stored resource definitions from the IMSRSC repository with the automatic import function or the IMPORT DEFN SOURCE(REPO) command.
  • Using the appropriate CREATE command (according to the type of resource definition you want to create).
When DRD is enabled for MODBLKS resources, runtime descriptor definitions can be created by:
  • Importing the stored descriptor definitions from the RDDS with the automatic import function or the IMPORT DEFN SOURCE(RDDS) command.
  • Importing the stored descriptor definitions from the repository with the automatic import function or the IMPORT DEFN SOURCE(REPO) command.
  • Using the appropriate CREATE command (according to the type of descriptor definition you want to create).
When DRD is enabled for MSC resources, runtime resources can be created by:
  • Importing the stored resource definitions from the IMSRSC repository with the automatic import function.
  • Importing the stored resource definitions from the DFSCLL3x member of the IMS.SDFSRESL data set with the automatic import function.
  • Using the appropriate CREATE command (according to the type of resource definition you want to create).

The resource and descriptor definitions that you create dynamically using either the CREATE command or the IMPORT DEFN command exist only during the current execution of the IMS system, and they are recoverable across a warm or emergency restart.

To preserve the MODBLKS resource and descriptor definitions across a cold start, export the MODBLKS definitions to an RDDS or an IMSRSC repository before IMS terminates. Or, if the AUTOEXPORT parameter is set to AUTO, RDDS, or REPO in the DFSDFxxx PROCLIB member, the MODBLKS resources will be exported automatically at the next IMS checkpoint. You can then import the stored MODBLKS definitions from the RDDS or the repository back into IMS either during cold start processing by using the automatic import function, or when IMS is up and running by using the IMPORT DEFN command.

To preserve MSC resource definitions across a cold start, export the MSC definitions to an IMSRSC repository by using the automatic export function. The MSC resource definitions are automatically exported to the repository at IMS checkpoint time and before IMS shutdown. You can then import the MSC definitions during cold start processing from the IMSRSC repository by using the automatic import function.

Each resource or descriptor definition can be created individually, unlike the online change process where either all resource definitions must be created or no resource definitions are created.