1)The extent to which a program continues working reasonably despite invalid user's inputs: Correctness Robustness Portability Performance

2)Portability is the most important quality for: Real-time systems Distributed systems Information systems Critical systems

3)Perfective maintenance means: Adding new functional requirements Improving the software qualities Fixing errors Adapting software with new tools

4)In an FSM: A transition can end up to several states

A transition can end up to a single state Only one state can be performed at a time

Several states can be performed at a time