What is System? What are the characteristics of system?

What is System? What are the characteristics of system?The word system is derived from the Greek word "Systema" which means an organized relationship among the functioning components. A system can be defined as any set of objects and ideas, and their interrelationships, which are ordered to a common goal or purpose.
Library management system, Computer system, accounting system, production system, etc...
Simply, it is a set of elements joined together for a common objective. It can also be defined as the combination of people, devices and methods interrelated in working towards a common goal. Any system can not do any jobs without sub-systems.

A sub-system is a part of large system. i.e an organization is a system and the parts like departments, accounting, information units etc are sub-systems.

Examples : business system, computer system, information system, etc.. Every system has boundary within, which it lies and outside of which is it's environment.

  1.  There is some specifics purpose or function that must be fulfilled or performed. 
  2. There are a number of components that can be identified as the necessary ingredients of the problem; each components has a verity of attributes that implicitly, physically and behaviorally and necessary for description. 
  3. These components are inter-related in some manner, satisfying interface consistency between the components. 
  4. These are constraints that restrict the system's behavior and the individual component response.