IMS™ subsystem access

FM/IMS allows you to control the way in which your IMS™ subsystems are accessed as described in the following sections.

For more information on these controls, see Controlling access to the subsystems and FM/IMS options.

Read only subsystems

FM/IMS allows you to define a subsystem as read-only. If a subsystem is defined as read-only, only the FM/IMS non-update functions - Browse, Batch Browse, Extract and Print - can be run against databases in the subsystem; FM/IMS prevents users running the update functions - Edit, Batch Edit, Load, Initialize and Delete/Define.

BMP mode only and DLI mode only subsystems

FM/IMS allows you to define a subsystem as BMP mode only or DLI mode only. If a subsystem is defined as BMP mode only, databases in the subsystem can only be accessed in BMP mode. If a subsystem is defined as DLI mode only, databases in the subsystem can only be accessed in DLI mode.

Static PSB only and dynamic PSB only subsystems

FM/IMS allows you to define a subsystem as static PSB only or dynamic PSB only. If a subsystem is defined as static PSB only, then only static PSBs can be used to access databases in the subsystem. If a subsystem is defined as dynamic PSB only, then only dynamic PSBs can be used to access databases in the subsystem.

Dynamic allocation only subsystems

FM/IMS allows you to define a subsystem as dynamic allocation only. If a subsystem is defined as dynamic allocation only, FM/IMS enforces the use of the database data sets specified in the DFSMDA dynamic allocation modules, when accessing databases in the subsystem in DLI mode.

Enforcing the usage and retention of IMS logs

FM/IMS allows you to force FM/IMS functions to use an IMS™ log when they are run in DLI mode and use a PSB that has update intent. FM/IMS also allows you to force the user to keep the log when the function ends.