Not for handing in, just for thinking about. Talk to other groups, assistants, or even people who have taken the course in previous years.
Brainstorm some techniques you could use to prevent a user from being hopelessly stranded, waiting for an elevator that will never arrive. Think about the worst-case behaviour of the system.
- What if the software controlling one of the elevators suddenly crashes?
- What if it doesn't crash, but hangs?
- What if a message between machines is lost?
- What if the network cable is suddenly disconnected? Then re-connected?
- What if a user of the system is being a troll?
- What if the elevator car never arrives at its destination?