Structured Systems Analysis And Specification

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Structured Systems Analysis and Design Requirements Collection and Specification Structured systems analysis and design method (SSADM), originally released as methodology, is a systems approach to the analysis and design of information systems. SSADM was produced for the Central Computer and Telecommunications Agency (now Office of Government Commerce), a UK government office concerned with the use of technology in government, from 1980 onwards. SSADM techniques The three most important techniques that are used in SSADM are as follows: Logical data modeling The process of identifying, modeling and documenting the data requirements of the system being designed. The result is a data model containing entities (things about which a business needs …show more content…

Stage 4 – Technical system options This stage is the first towards a physical implementation of the new system. Like the Business System Options, in this stage a large number of options for the implementation of the new system are generated. This is narrowed down to two or three to present to the user from which the final option is chosen or synthesized. However, the considerations are quite different being: • the hardware architectures • the software to use • the cost of the implementation • the staffing required • the physical limitations such as a space occupied by the system • the distribution including any networks which that may require • the overall format of the human computer interface All of these aspects must also conform to any constraints imposed by the business such as available money and standardization of hardware and …show more content…

Data Flow Dataflow is a software architecture based on the idea that changing the value of a variable should automatically force recalculation of the values of variables which depend on its value. Dataflow embodies these principles, with spreadsheets perhaps the most widespread embodiment of dataflow. For example, in a spreadsheet you can specify a cell formula which depends on other cells; then when any of those cells is updated the first cell's value is automatically recalculated. It's possible for one change to initiate a whole sequence of changes, if one cell depends on another cell which depends on yet another cell, and so on. The dataflow technique is not restricted to recalculating numeric values, as done in spreadsheets. For example, dataflow can be used to redraw a picture in response to mouse movements, or to make a robot turn in response to a change in light level. Logical Data

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