07-05-2012, 11:11 AM
INTRODUCTION TO SYSTEM ANALYSIS AND DESIGN
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INTRODUCTION
Systems are created to solve problems. One can think of the systems
approach as an organized way of dealing with a problem. In
this dynamic world, the subject System Analysis and Design (SAD),
mainly deals with the software development activities.
OBJECTIVES
After going through this lesson, you should be able to
l define a system
l explain the different phases of system development life cycle
l enumerate the components of system analysis
l explain the components of system designing
DEFINING A 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.
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:
l Preliminary study
l Feasibility study
l Detailed system study
l System analysis
l System design
l Coding
l Testing
l Implementation
l Maintenance
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 studies
the system) and places it before the user management.