After the completion of requirements analysis for a system, System design activity takes place for the alternative, which is selected by management. The system design phase usually consists of following three activities:
i) Reviewing the system‘s informational and functional requirements;
ii) Developing a model of the new system, including logical and physical specifications of outputs, inputs, processing, storage, procedures and personnel;
iii) Reporting results to management.
The system‘s design must conform to the purpose, scale and general concepts of the system that management approved during the requirements analysis phase. Therefore, users and system analysts must review each of these matters again before starting the design because they establish both the direction and the constraints that system developers must follow during rest of the activities.
As mentioned above, system design involves first logical design and then physical construction of a system. When analysts formulate a logical design, they write the detailed specifications for the new system, they describe its features; the outputs, input files, databases and procedures, all in a manner.