What is System?

A system is a collection of components (subsystems) that work together to realize some objective. For example, the library system contains librarians, books, and periodicals as components to provide knowledge for its members.

Basic System Module

Every system has three activities or functions. These activities are input, processing and output.

Input: It involves capturing and assembling elements that enter the system to be processed. Inputs to the system are anything to be captured by the system from its environment. For example, raw materials.
Processing: It involves transformation processes that convert input to output. For example, a manufacturing process.
Output: It involves transferring elements that have been produced by a transformation process to their ultimate destinations. Outputs are the things produced by the system and sent into its environment. For example, finished products.

The system also includes other two additional activities. These activities include feedback and control.

Feedback: It is data about the performance of a system. It is the idea of monitoring the current system output and comparing it to the system goal. Any variation from the goal are then fed back in to the system and used to adjust it to ensure that it meets its goal. For example, data about sales performance is feedback to a sales manager.
Control: It involves monitoring and evaluating feedback to determine whether a system is moving toward the achievement of its goals. The control function then makes necessary adjustments to a system’s input and processing components to ensure that it produces proper output. For example, a sales manager exercises control when reassigning salespersons to new sales territories after evaluating feedback about their sales performance.

Theoretical approaches to systems have introduced many generalized principles. Goal setting is one such principle. It defines exactly what the system is supposed to do. There are principles concerned with system structure and behavior. System boundary is one such a principle. This defines the components that make up the system. Anything outside the system boundary is known as system environment. A system can be made up of any number of subsystems. Each subsystem carries out part of the system function i.e. part of the system goal. The subsystems communicate by passing messages between themselves.

Several systems may share the same environment. Some of these systems may be connected to one another by means of a shared boundary, or interface. A system that interacts with other systems in its environment is called open system. Finally, a system that has the ability to change itself or environment in order to survive is called an adaptive system.