Demarco's Systems Analysis Method
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 different terms for this document: Functional Specification, Design Specification, Memo of Rationale, Requirements Document, etc. But DeMarco introduced a new term called the Target Document. The analyst is the third person or the middleman between the user and the development team. The user decides what has to be done and the development team makes it possible. With the Target Document, the analyst will bridge the gap between the user and the development team. The process of putting this document together and getting it accepted by all parties is called specification. Whether the whole specification process leads to a successful result or not will depend on its product which is the target document. As planned, if the Target Document is capable of performing its task, to serve as a model of the new system, that shows the success of the specification process.
The Structured Specification has several components:
1. Data Flow Diagram (DFD): Depicts processes and the flow of data between them. DFD doesn’t depict conditional logic or flow of control between modules.
2. Data Dictionary: A repository of definitions for data elements, files, and processes.
3.
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 different terms for this document: Functional Specification, Design Specification, Memo of Rationale, Requirements Document, etc. But DeMarco introduced a new term called the Target Document. The analyst is the third person or the middleman between the user and the development team. The user decides what has to be done and the development team makes it possible. With the Target Document, the analyst will bridge the gap between the user and the development team. The process of putting this document together and getting it accepted by all parties is called specification. Whether the whole specification process leads to a successful result or not will depend on its product which is the target document. As planned, if the Target Document is capable of performing its task, to serve as a model of the new system, that shows the success of the specification process.
The Structured Specification has several components:
1. Data Flow Diagram (DFD): Depicts processes and the flow of data between them. DFD doesn’t depict conditional logic or flow of control between modules.
2. Data Dictionary: A repository of definitions for data elements, files, and processes.
3.