Objectives: Introduction Over View of System Analysis and Design
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| 6.1 Introduction Analysis is the heart of the process. It is the key component of the first two phases of the cycle. In analysis the present system, the analyst collects a great deal of relatively unstructured data through interviews, questionnaires, onsite observations, procedures manuals, and the like. The traditional approach is to organize and convert the data though system flowcharts, which support future developments of the system and simplify communication with the user. But the system flowchart represents a physical rather than a logical system. It makes it difficult to distinguish between what happens and how it happens in the system. There are other problems with the traditional approach. 1. The system life cycle provides very little quality control to ensure accurate communication from user to analyst. They have no language in common. 2. The analyst is quickly overwhelmed with the business and technical details of the system. Much of the time is spent gathering information. The details are needed and must be available, but the analyst does not have the tools to structure and control the details. 3. Present analytical tools have limitations. a. English narrative descriptions of a system are often too vague and make it difficult for the user to grasp how the parts fit together. Furthermore, English is inherently difficult to use where precision is needed. b. System and program flowcharts commit to a physical implementation of the system before on has complete understanding of its logical requirements. 4. Problems also relate to system specifications- a. System specifications are difficult to maintain or modify. A simple change in the user’s requirements necessitates changes in several parts of the document. b. They describe user requirements inn terms of physical hardware that will implement the system rather than what the user wants the system to doc. They are monolithic and redundant that is, to find out information about a particular part of the system, the user has to search the entire document. Furthermore, the same information is found in numerous locations with no cross-reference. Because of these drawbacks, the analyst needs something analogous to the architect’s blueprint as a starting point for system design. It is away to focus on functions rather than physical implementation. One such tool is the data flow diagram (DFD). There are other tools as well. The use of several tools in structured analysis, including the following 1. Data flow diagram (DFD). 2. Data dictionary. 3. Structured English. 4. Decision trees. 5. Decision tables. System analysis is about understanding situations, not solving problems. Effective analysts therefore emphasize investigation and questioning to learn how a system currently operates and to identify the requirements users have fora new or modified one. Only after analysts fully understand the systems are they able to analyze it and assemble recommendations for systems design. The manner in which a systems investigation is conducted will determine whether the appropriate information is gathered. In turn, having the right information influences the quality of the application that follows. In other words, good system design, whether developed through the SDLC method, prototyping, or structured methods, begins by documenting the current system and properly diagnosing systems requirements. Download 0.94 Mb. Share with your friends:
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