SAD

                                           System’s Concept 

Term system is derived from the Greek word ‘Systema’ which means an organized relationship among functioning units or components.


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 Definition of System:
A system is an orderly grouping of interdependent components linked together according to a plan to achieve a specific objective.
or
 system is an arrangement of element or components that perform a specific task.
or
 A system is a set of interacting or interdependent component parts forming a complex/intricate whole.
Every system is delineated by its spatial and temporal boundaries, surrounded and influenced by its environment, described by its structure and purpose and expressed in its functioning.

Characteristics of a System

• Organization 

• Interaction 

• Interdependence

• Integration 

• Central Objective 

• Organization-It implies structure and order.

• Interaction-It refers to manner in which each component functions with other components of the system.

• Interdependence-Units/parts are dependent on each other. 

• Integration-The parts of a system work together within the system even though each part performs a unique function. 

• Central Objective-Objective may be real or stated. All the components work together to achieve that particular objective

Some systems share common characteristics, including:

 A system has structure, it contains parts (or components) that are directly or indirectly related to each other;

⦁ A system has behavior, it exhibits processes that fulfill its function or purpose;

⦁ A system has interconnectivity: the parts and processes are connected by structural and/or behavioral relationships;

⦁ A system's structure and behavior may be decomposed via subsystems and sub-processes to elementary parts and process steps;

⦁ A system has behavior that, in relativity to its surroundings, may be categorized as both fast and strong.

*ELEMENTS OF A SYSTEM: AN EXAMPLE

Following are considered as the elements of a system in terms of Information systems: –

⦁ Input

⦁ Output

⦁ Processor

⦁ Control

⦁ Feedback

⦁ Boundary and interface

⦁ Environment

1. INPUT: Input involves capturing and assembling elements that enter the system to be processed. The inputs are said to be fed to the systems in order to get the output. For example, input of a 'computer system' is an input unit consisting of various input devices like a keyboard, mouse, joystick etc.

2. OUTPUT: That element that exists in the system due to the processing of the inputs is known as output. A major objective of a system is to produce output that has value to its user. The output of the system maybe in the form of cash, information, knowledge, reports, documents etc. the system is defined as output is required from it. It is the anticipatory recognition of output that helps in defining the input of the system. For example, output of a 'computer system' is an output unit consisting of various output devices like the screen and the printer etc.

3. PROCESSOR(S): The processor is the element of a system that involves the actual transformation of input into output. It is the operational component of a system. For example, processor of a 'computer system' is central processing unit that further consists of arithmetic and logic unit (ALU), control unit and memory unit etc.

4. CONTROL: The control element guides the system. It is the decision-making sub-system that controls the pattern of activities governing input, processing and output. It also keeps the system within the boundary set. For example, control in a 'computer system' is maintained by the control unit that controls and coordinates various units by means of passing different signals through wires.

5. FEEDBACK: Control in a dynamic system is achieved by feedback. Feedback measures output against a standard input in some form of cybernetic procedure that includes communication and control. The feedback may generally be of three types viz., positive, negative and informational. The positive feedback motivates the system. The negative indicates need of an action. The feedback is a reactive form of control. Outputs from the process of the system are fed back to the control mechanism. The control mechanism then adjusts the control signals to the process on the basis of the data it receives. Feed forward is a protective form of control. For example, in a 'computer system' when logical decisions are taken, the logic unit concludes by comparing the calculated results and the required results.

6. BOUNDARY AND INTERFACE: A system should be defined by its boundaries - the limits that identify its components, processes and interrelationships when it interfaces with another system. For example, in a 'computer system' there is a boundary for the number of bits, the memory size etc. that is responsible for different levels of accuracy on different machines (like 16-bit, 32-bit etc.). The interface in a 'computer system' may be a CUI (Character User Interface) or a GUI (Graphical User Interface).

7. ENVIRONMENT: The environment is the 'super system' within which an organization operates. It excludes input, processes and outputs. It is the source of external elements that impinge on the system. For example, if the results calculated/the output generated by the 'computer system' are to be used for decision-making purposes in the factory, in a business concern, in an organization, in a school, in a college or in a government office then the system is same but its environment is different.

Types of System

• Physical or Abstract 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 or Probabilistic System 

• 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 makes water. 

• Probabilistic System – It shows probable behavior. The exact output is not known. For example: weather forecasting, mail delivery. 

Social, Human Machine, Machine System 

• 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 and Manufactured

• 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, Trains.

Permanent or Temporary System 

• 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 and Non Adaptive System 

• Adaptive System- respond 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. ex

chemical reactions