Demarco's Systems Analysis Method Essay

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Outline the structured specification produced by DeMarco’s systems analysis method.

What do you think are the main advantages of specifying a computer-based system by means of such a structured specification?

How adequately, do you think, does this method deal with the human aspects of information systems changes?

According to DeMarco’s structured analysis, it is a study of a problem leading to the specification of a new system prior to implementation of that system. DeMarco also makes it very clear in his book (The Structured Analysis and System Specification – a Yourdon Book) that the most important product of the analysis phase of the life cycle is the specification document. Different organizations are using
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3. Transform Descriptions: Use Structured English, Decision Tables, and Decision Trees to document the internals of the DFD in a detailed manner.
Structured English is a specification language. It uses a limited vocabulary and a limited syntax.
The vocabulary consist only of
- imperative English language verbs
- terms defined in the Data Dictionary
- certain reserved words for logic formulation The syntax of a Structured English is limited to
- simple declarative sentence
- closed-end decision construct
- closed-end repetition construct Decision Table is a table of entries that are actions and policies. Decision Tree is a graphic presentation of a Decision Table.

The qualities of DeMarco’s Structured Specification can be summarized in 7 steps:

1. It should be graphic: An easy to understand presentation of the subject matter is depicted by Data Flow Diagrams. DFDs give a meaningful picture of what is being specified.

2. It should be partitioned: The system is decomposed into processes. The processes are the basic elements on the Data Flow Diagram.

3. It should be rigorous: A highly detailed documentation of the interfaces is provided by the Data
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