
172 Chapter 3
The direction of the arrow indicates the direction of the data flow. The
resulting diagram should show graphically all the communications
between the various tasks within the system. Any significant data stor-
age associated with the various tasks are also noted on the diagram. A
variable list and dictionary is then compiled, based on the information
in the data flow diagram. The resulting documentation will then form
the basis of all system-level variable definitions in the next chapters. So,
designers are encouraged to be as accurate as possible in both the diagram
and the resulting variable documentation. Note: The usefulness ...