21. An external entity a person, place, or thing within the
21. An external entity is a person, place, or thing within the system that transforms data.
22. A physical data flow diagram (DFD) uses bubbles to specify where, how, and by whom a system's processes are accomplished.
23. When the context diagram and the level 0 diagram have equivalent external data flows, the DFDs are said to be balanced.
24. The successive subdivision, or exploding, of logical data flow diagrams (DFDs) is called bottom up partitioning.
25. A systems flowchart is a graphical representation of both the physical and logical features of an information system.
26. Processes that handle other-than-normal situations are called exception routines.
27. Information processing activities retrieve data from storage, transform data, or file data.
28. An acceptance stub is a data flow that leaves a bubble but does not go to any other bubble or file and indicates processing that is performed in other than normal situations.
29. In an enterprise system, we would have one data store/disk symbol labeled "enterprise database" instead of two or more data store symbols.
30. When we convert to an enterprise system, reengineered processes often result from the installation and can cause changes throughout the systems flowcharts.