Groups or functions are used to group together components that work together to perform a certain function as show in the previous sample model.
Hardware, software and external components are so named to easily distinguish items that can be replaced (hardware), software which might need to be reloaded and finally external influences (things that are not part of the system but can influence it such as humidity, temperature, etc)
Redundant groups gives the user the ability to define redundant systems in the model, which will have the following behavior that differs from the standard troubleshooting rules:
1.) When any one component that is part of a redundant group fails, the system output will not be affected. This will allow the system to indicate that it is still functional although there is a failure in the system which is covered by a redundant circuit.
