MFS Device Characteristics table

The MFS Device Characteristics table (DFSUDT0x) is generated during system definition for the 3270 or SLU 2 devices defined as TYPE=3270-An in the TYPE or TERMINAL macro statement.

The 'x' in DFSUDT0␠x corresponds to the parameter specified on the SUFFIX= keyword of the IMSGEN macro.

The MFS Device Characteristics table can be updated with the MFS Device Characteristics Table utility (DFSUTB00), which allows updates to the table without system regeneration. Each entry in the table contains the user-defined device type symbolic name (3270-An), associated screen size (from SIZE= parameter), and physical terminal features (from FEAT= parameter). Different specifications of the physical terminal features (FEAT= parameter) for the same device type symbolic name cause separate entries to be generated in the MFS Device Characteristics table.

MFS source definitions specify TYPE=3270-An and FEAT as operands on the DEV statement. For the specified device type, MFS extracts the screen size from the specified DFSUDT0␠x in the IMS.SDFSRESL library.

The MFS Language utility (DFSUPAA0) uses the screen size, feature, and device type specifications to build a DIF/DOF member in the IMS.FORMAT library to match the IMS system definition specification. Because the screen size is specified only during IMS system definition, an IMS system definition must be performed before execution of the MFS Language utility for user-defined formats with DEV TYPE=3270-An.

The MFS Device Characteristics table is created during stage 2 of IMS system definition using the same suffix as the IMS composite control block, nucleus, and security directory block modules as specified in the SUFFIX= keyword of the IMSGEN macro. If terminals defined with ETO are added to the system, the MFS Device Characteristics Table utility can be used to add to or update the table without regenerating the system definition.

The alphanumeric suffix (x) of the table name (DFSUDT0␠x) is the level identification for the version of the table to be read. The x suffix can also be specified using the DEVCHAR= parameter of the EXEC statement for the MFSUTL, MFSBTCH1, MFSTEST, and MFSRVC procedures. Repetitive use of the same suffix by the MFS Language utility causes the same version of the MFS device Characteristics table to be read from the IMS.SDFSRESL library.

If an MFS Device Characteristics table is required, and either no suffix was provided or the suffixed table is not present in the IMS.SDFSRESL library, the MFS Language utility attempts to load the IMS Device Characteristics table using the default name (DFSUDT00).

Note: If no default table (DFSUDT00) was created at system definition a failure will result.

During the logon process for an ETO terminal, the MFS Device Characteristics table is used to determine the MFS device type for the terminal. The screen size from the BIND unique data and the device features from the ETO logon descriptor are used as search arguments.

Associate only one symbolic name with a given screen size. Establish a standard for relating the device type symbolic name to the screen size.

Recommendation: Use the listed screen sizes for each of the user-defined symbolic names:

User-Defined Symbolic Name: Screen Size
3270-A1: 12×80
3270-A2: 24×80
3270-A3: 32×80
3270-A4: 43×80
3270-A5: 12×40
3270-A6: 6×40
3270-A7: 27×132
3270-A8: 62×160