Characteristics of a System

Systems have very specific common characteristics which help in its identification. They are:

1. Systems have a specific structure which is defined by its components (entities/subsystems) and processes (interrelationships between its components). A system is a collection of interrelated entities and/or subsystems which can be analyzed. It is possible to understand the specific structure of a system. However, in some systems complete knowledge may not be available but in most cases the fundamental entities and their interrelations are known.
2. Systems are a model of reality-a system is an abstraction of reality. It is created to comprehend the nuances of a real-world condition and understand the interrelationships of subsystems in such real-world conditions in greater clarity.
3. A system has a purpose-a system performs a function. It has a reason for its existence. The purpose in most cases is the output of the system and in a way the output defines the purpose of the system.
4. Systems have inputs and outputs. Outputs are produced by processing the inputs-a system (unless of theoretical interest and fully closed), interacts with the environment by taking in input and then after processing the input produces the output.
5. Systems have performance that can be measured in terms of its output-a system will have measures of performance. In most cases, the performance of the system is a function of its input and output.
6. A system serves a client-the system will have a utility and hence, a client for it. The client can also be another system.
7. The components that make up a system have functional as well as structural interrelationships with each other.
8. A system has an environment-a system cannot exist in isolation. It exists in an environment. The environment reacts with it.
9. Each subsystem also has a purpose and a measure of purpose.