Monitor (OS)

Monitor is a software module that uses condition variables for signalling.

  • Unused signals are lost (!= semaphores)

Chief characteristics

  • Local data variables are accessible only by the monitor (⇒ shared data in monitor is “safe”)
  • Process enters monitor by invoking one of its procedures (⇒ controlled entry)
  • Only one process may be executing in the monitor at a time (⇒ mutex)