System Analysis and Design
Term system is derived from the Greek word 'Systema‘ which means an organized relationship among functioning units or components.
A system is an orderly grouping of interdependent components linked together according to a plan to achieve a specific objective.
1 Characteristics of a System
2 Elements of a System
Outputs and Inputs
Boundaries and Interface
3 Types of System
Physical – These are tangible entities that may be static or dynamic in operation. For example- parts of a computer center are the desks, chairs etc. that facilitate operation of the computer. They are static and a programmed computer is dynamic.
Abstract System – These are conceptual or non physical entities. For example- the abstract conceptualization of physical situations. A model is a representation of a real or planned system. A model is used to visualize relationships.
Deterministic System – It operates in a predictable manner and the interaction between parts is known with certainty. For example: Two molecules of hydrogen and one molecule of oxygen make water.
Probabilistic System – It shows probable behavior. The exact output is not known. For example: weather forecasting, mail delivery.
Social System- It is made up of people. For example: social clubs, societies
Human Machine System- When both human and machines are involved to perform a particular a particular task to achieve a target. For example: - Computer.
Machine System- Where human interference is neglected. All the tasks are performed by the machine.
Natural System- The system which is natural. For example- Solar system, Seasonal System.
Manufactured System- System made by man is called manufactured system. For example- Rockets, Dams, and Trains.
Permanent System- Which persists for long time. For example- policies of business.
Temporary System- Made for specified time and after that they are dissolved. For example- setting up DJ system.
Adaptive System- responds to change in the environment in such a way to improve their performance and to survive. For example- Human beings, animals.
Non Adaptive System-The system which doesn‘t respond to the environment. For example- Machines
Open System – It has many interfaces with its environment. It interacts across its boundaries, it receives inputs from and delivers outputs to the outside world. It must adapt to the changing demands of the user.
Closed System – It is isolated from the environmental influences. A completely closed system is rare.