Using the MFSDCT utility (DFSUTB00)

IMS searches the device characteristics table in order to locate MFS device information during session initiation only in certain situations.

IMS searches the device characteristics table during session initiation in the following circumstances:
  • The screen size is overridden.
  • The model value in PSERVIC is X'00', X'7E', or X'7F'.

The MFSDCT utility (DFSUTB00) enables you to define screen sizes that are not defined during IMS system definition. The MFSDCT utility uses MFS device descriptors in PROCLIB member DFSDSCMx and DFSDSCTy, without performing an IMS system definition. The new screen size definitions are added to those that are already defined.

The MFS utility does the following:
  • Reads device descriptors from IMS.PROCLIB members DFSDSCMx and DFSDSCTy.
  • Builds one device descriptor table entry statement for each new device descriptor.
  • Terminates if no descriptors are specified.
  • Optionally loads the existing device characteristics table from IMS.SDFSRESL, and builds one entry statement for each existing table entry.
  • Passes the table entry statements and the DCTBLD and MFSINIT macros as input to assembler.
  • Prepares assembler output as a new or updated device characteristics table, as well as a new set of default MFS format definitions. Output is in separate files for subsequent processing.

The MFSDCT utility procedure is found in IMS.PROCLIB. You must evaluate the screen size requirements and code MFS device descriptors to meet those requirements. The MFSDCT utility must generate all possible combinations of screen sizes and features that your installation might require.

To use the MFSDCT utility, follow these steps:

Procedure

  1. Execute DFSUTB00 (the MFSDCT utility).
  2. Assemble the new device characteristics table.
  3. Link edit the new device characteristics table into IMS.SDFSRESL.
  4. Execute phase 1 of the MFS Language utility in order to generate new default MFS format control blocks.
  5. Execute phase 2 of the MFS Language utility; the new default MFS formats are loaded into IMS.FORMAT.

Problems with the device characteristics table are often indicated by error messages DFS3646I and DFS3672I during logon processing.