IMS™ region controller parameters

FM/IMS functions that access databases invoke the IMS™ region controller as a subtask. You specify the default values for the parameters passed to the IMS™ region controller when you customize the FM/IMS installation options module.

In the FM/IMS installation options module customization, you specify defaults for the following options:
  • Whether or not FM/IMS functions use Database Recovery Control (DBRC) when they are run in DLI mode.
  • Whether or not FM/IMS functions use an Internal Resource Lock Manager (IRLM) when they are run in DLI mode.
  • The 4-byte z/OS® subsystem name assigned to the Internal Resource Lock Manager.
  • Whether or not dynamic backout is to be performed when an IMS™ pseudo-abend occurs in a File Manager/IMS function running in DLI mode.
  • (If the IMS™ subsystem is part of a Remote Site Recovery (RSR) complex) the Global Service Group (GSG) name and the Transport Manager Instance (TMI) name that FM/IMS functions are to use when they are run in DLI mode.
  • The parallel DL/I option that FM/IMS functions are to use when they are run in BMP mode.
  • The number of Fast Path database buffers to be made available in the Common Service Area (CSA) when a Fast Path region is activated.
  • The number of additional page-fixed buffers to be made available to a Fast Path region if the normal allotment is used.
  • The maximum number of locks that a File Manager/IMS function is allowed to hold at one time.

In the FM/IMS installation options module customization, you also specify whether or not the user can override the values that you specify for the above options.

For more information on specifying the IMS™ region controller parameters, see Specifying the parameters passed to the IMS region controller.