what is structure analysis and design- csmates.com

Software development has become more complex in the last decades. The economic pressure and competition for software companies has grown. Software engineering is the effort to apply disciplined and repeated engineering techniques and methodologies to software development in order to cope with complexity and produce high quality software system economically.

Applying Structured Analysis and Structured Design (SASD) to a software development process can help producing a complete and consistent specification that will in turn lead to fewer problems in the implementation stages.

system and analysis design in software engineering (SAD or SASD)

Structured Analysis and Structured Design 

Structured analysis is the activity of deriving a structured model of the requirements of a system. Structured design, on the other hand, is the development of a blueprint of a computer system solution to a problem, having the same components and interrelationship as the original problem had. Both structured analysis and structured design techniques are based upon the idea of a block-box description of a system.

Structured analysis and structured design in its various manifestations became the mst widely used and sophisticated procedural analysis and design method during the 1970s and1980s. It was supported by most CASE tools, documented in many popular books, was extended for special domains (such as real-time systems), and was used in newer and older versions of its many variations.

Structured analysis and structured design are both outgrowth of structured programming concepts and techniques, and the early of modular design. SASD applies structured programming constructs to process and data definitions, and builds upon ideas of modularity offered by David Parnas.

The credit to early recognition of a structured analysis technique goes to Douglas Ross, who developed an technique called Structured Analysis and Design Technique (SADT). The SADT encourages the analyst to begin by asking about the objectives of the system, before progressing to analysis details and eventually the implementation details.

The early SADT model didn't include a data dictionary for the process, which have become standard elements of SASD. Tom Demacro consolidated and simplified the model's graphics by adding some of the notations offered by Edward Yourdan, which made it less formidable looking and more accessible to a broad audience. 

Workers at IBM laid the foundation for a process-driven approach to software design and in 1979, Edward Yourdan popularized the method by a book, "The Practical Guide to Structured System Design". This book complied all of the good ideas from existing techniques, and integrated the good ideas from structured analysis.

An opposing camp in software design was the data-driven approach created by Micheal Jackson and Jean-Dominique Warnier. Their methods received more use in their own countries of England and France, respectively. Jackson extended the scope of data-driven design to include multitasking, which he called Jackson Structured Design. Composite structured design was suggested by Myers.


The major goal of SASD is to improve the quality and reduce the risk of failure. Behind this primary goal lie secondary goal:
  • Need to obtain a clear and complete specification.
  • Documentation for the system.
Therefore, SASD tackles reliability, flexibility, maintainability, and effectiveness goals by making visible and precise models that show analysis and design information.

Benefits of SASD

  • SASD creates the map of the system, and these maps can be used for traceability, maintenance, or enhancement activities in the future.
  • SASD places emphasis on analysis and design activities, rather than implementation. This encourages the project team to be thoughtful about the system's fundamental purpose and the engineering details.
  • The project team develops software documentation as they progress though development.

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