Introduction to System Analysis and Design (SAD)
System are created to solve Problems. One can think of the systemsapproch as an organised way of dealing with a problem. In this dynamic world, the subject system analysis and design, mainly deals with the software development activities.
This post include:-
* What is System?
* What are diffrent Phases of System Development Life Cycle? * What are the component of system analysis?
* What are the component of system designing?
What is System?
A collection of components that work together to realize some objectives forms a system. Basically there are three major components in every system, namely input, processing and output.
In a system the different components are connected with each other and they are interdependent. For example, human body represents a complete natural system. We are also bound by many national systems such as political system, economic system, educational system and so forth. The objective of the system demands that some output is produced as a result of processing the suitable inputs. A well-designed system also includes an additional element referred to as ‘control’ that provides a feedback to achieve desired objectives of the system.
SYSTEM LIFE CYCLE
System life cycle is an organizational process of developing and maintaining systems. It helps in establishing a system project plan, because it gives overall list of processes and sub-processes required for developing a system. System development life cycle means combination of various activities. In other words we can say that various activities put together are referred as system development life cycle. In the System Analysis and Design terminology, the system development life cycle also means software development life cycle. Following are the different phases of system development life cycle: * Preliminary Study
* Feasibility study
* Detailed system study
* System analysis
* System design
The different phases of system development life cycle is shown in this diagram Phases of System Development Life Cycle
PHASES OF SYSTEM DEVELOPMENT LIFE CYCLE
Let us now describe the different phases and related activities of system development life cycle. (a) Preliminary System Study
Preliminary system study is the first stage of system development life cycle. This is a brief investigation of the system under consideration and gives a clear picture of what actually the physical system is? In practice, the initial system study involves the preparation of a ‘System Proposal’ which lists the Problem Definition, Objectives of the Study, Terms of reference for Study, Constraints, Expected benefits of the new system, etc. in the light of the user requirements. The system proposal is prepared by the System Analyst (who studiesthe system) and places it before the user management. The management may accept the proposal and the cycle proceeds to the next stage. The management may also reject the proposal or request some modifications in the proposal. In summary, we would say that system study phase passes through the following steps: * Problem identification and project initiation
* Background analysis
* Inference or findings (system proposal)
(b) Feasibility Study
In case the system proposal is acceptable to the management, the next phase is to examine the feasibility of the system. The feasibility study is basically the test of the proposed system in the light of its workability, meeting user’s requirements, effective use of resources and of course, the cost effectiveness. These are categorized as technical, operational, economic and schedule feasibility. The main goal of feasibility study is not to solve the problem but to achieve the scope. In the process of feasibility study, the cost and benefits are estimated with greater accuracy to find the Return on Investment (ROI). This...
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