Environment and sub-system

Environment is context in which system operates and is major influence on system behaviour.
System receives inputs from and provides outputs to environment.
Systems change overtime.
“What does the system interact with?” – no absolute answer. Depends on perspective taken. The same applies to the boundary too.
Stakeholders have one view but asking whole group helps identify those elements that are important.
Sub-system
Systems made up of sub-systems, each a system in it’s own right.
They have own system purpose, boundary and it’s parent system will be the environment for the sub-system.