Info systems

• A system is a set of components that interact to accomplish some purpose.

• Systems are all around us, there are two types of system:
  • Natural System; a system that exists as part of nature.
    Examples : human body, solar system
  • Fabricated System; a system that has been built by people.
    Examples: automobile, accounting system

A system can be broken into subsystems. Most systems are in fact subsystems of some larger system.

• Example: human body
  • circulatory system
  • skeletal system
  • nervous system

A system can be open or closed.

• An open system is a system that interacts with its environment (ie receives input and produces output).
• A closed system does not interact with its environment.
• All ongoing systems are open, the closed system only exists as a concept.

Systems work best when they are in control, or when they operate within tolerable performance levels.

Example: humans operate best at 98.6 ^oF

All systems have acceptable levels of performance called standards, against which actual performances are compared. The information supplied by comparing actual results with the standards and then informing the control elements is called feedback.

Systems that can adjust their activities to acceptable levels continue to function. Those that cannot stop.