Explain and differentiate between Context Level and Level 0-01236
This subjective question is related to the book/course
vu eng101 English Comprehension.
It can also be found in
vu eng101 Mid Term Solved Past Paper No. 2.
This is the level of DFD which provides the least amount of details about the working of the system. Context DFDs have the following properties:
They always consist of single process and describe the single system. The only process displayed in the CDFDs is the process/system being analyzed. Name of the CDFDs is generally a Noun Phrase.
No System details are shown in the Contexts DFDs just context is shown. Input and output from and to the process are shown and interactions are shown only with the external entities.
In the context level DFDs no data stores are created. Ant dataflow from external entities are only directed toward the purported system and vice versa, no communication is show between external entities themselves.
The level 0 Diagram in the DFD is used to describe the working of the whole system. Once a context DFD has been created the level zero diagram or level "notdiagram is created. The level zero diagram contains all the apparent details of the system. It shows the interaction between a numbers of processes and may include a large number of external entities. At this level it is the duty of the designer to keep a balance in describing the system using the level 0 diagram. Balance means that he should give proper depth to the level 0 diagram processes. Because placing too much details and showing all of the miniature processes in the level 0 diagrams makes it too much complex. On the other hand it is also not recommended to just ignore even larger processes of the system, because in such a case although the level 0 DFD will become simple but now we will have to create large number of detail DFDs. So a balance in describing the system should be kept so that the depth of the Level 0 DFD is manageable.
