Planning for MFS

After you implement ETO dynamic terminal support, the number and diversity of terminal types is likely to increase. When a terminal dynamically establishes an IMS session, MFS formats might not be available for the device type that is requesting the session.

You can solve this problem by:

  • Restricting device types to only those that are used in the MFS definitions for your application programs.
    Recommendation: Use the Logon exit routine (DFSLGNX0) to select the desired logon descriptor.
  • Extending the MFS device output formats to include the new terminal types that connect to the IMS.
    Recommendations:
    • Use the MFS Generation utility (MFSGU) facilities, such as the STACK statement, to make creating these additional formats easier.
    • Use the MFSDCT utility (DFSUTB00) to avoid needing to perform an IMS generation.

Often, multiple device types have similar or identical capabilities, so the distinction of device type might not be important to your environment. Although IMS application programs are usually not sensitive to device type, such a dependency can exist. For example, MFS can create different input messages from the same input data stream, due to differences in the format specification for device input.