Processing part

2

The instructions in the processing parts of an application program can be written in assembler language or in a higher-level language, such as PL/I or COBOL. If written in assembler language, the instructions can be blended with the communication instructions in the program. But more commonly, as shown in Figure 1, the processing parts 2 are separate and request data communication services by calling or branching to the communication part 3 of the program. Many programs contain several processing parts (routines or modules) that use a common communication part.