
Principles of operation
-----------------------

- For running applications we just register the PID to send the application
  a signal upon expiration of the alarm (SIGALRM, which might become a
  problem, maybe we should use SIGUSR or SIGURG SIGVTALRM).
- We must be able to register the application that registered the alarm.
  In case the application has ended before the alarm has expired the
  application has to be started again.
