Storage, Scratch, and Queue Management › Using the Terminal Screen To Transmit Data

Using the Terminal Screen To Transmit Data

You can transfer small amounts of alphanumeric data between tasks by using map data fields defined with the following attributes:

• Dark
• Protected
• MDT set on (nonpageable maps only)

For example, you can convert a record's db-key to display format and transmit the reformatted db-key in the map data stream to allow for DB-KEY retrieval on subsequent database access. You can also transmit the next task code to be invoked by a program.

The terminal screen is ideal for transmitting small amounts of data; more than a small amount of data can affect transmission time.

Example of Transmitting Screen Data

The program excerpt below uses the terminal screen to transmit the db-key of a database record to be modified. This allows for more efficient database access.

The program uses the record's db-key, which was transmitted in the map data stream, to retrieve the EMPLOYEE record.

 01  MAP-WORK-REC.
     05 WORK-DEPT-ID        PIC 9(4).
     05 WORK-EMP-ID         PIC 9(4).
     05 WORK-FIRST          PIC X(10).
     05 WORK-LAST           PIC X(15).
     05 WORK-ADDRESS        PIC X(42).
     05 WORK-DEPT-NAME      PIC X(45).
     05 DARK-DBKEY          PIC X(12).
     05 RETRIEVE-DBKEY      PIC S9(8) COMP.
 PROCEDURE DIVISION.
     BIND MAP EMPMAP.
     BIND MAP EMPMAP RECORD MAP-WORK-REC.
     MAP IN USING EMPMAP.
     IF WORK-EMP-ID NOT NUMERIC
        GO TO U100-INVALID-EMP-ID.
*
     COPY IDMS SUBSCHEMA-BINDS.
     READY.
*** CHANGE DARK-DBKEY FROM DISPLAY TO COMP ***
     MOVE DARK-DBKEY TO RETRIEVE-DBKEY.
     OBTAIN EMPLOYEE DB-KEY IS RETRIEVE-DBKEY
        ON DB-REC-NOT-FOUND
            GO TO U100-INVALID-DBKEY.
*
     MOVE WORK-FIRST  TO EMP-FIRST-NAME-0415.
     MOVE WORK-LAST   TO EMP-LAST-NAME-0415.
     MOVE WORK-ADDRESS TO EMP-ADDRESS-0415.
     MODIFY EMPLOYEE.
     FINISH.
*** MAP OUT PROCESSING AND ERROR ROUTINES ***
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