Comments on prevention of system deadlocks

Abstract

Habermann's method of deadlock prevention is discussed, where deadlock is defined as a system state from which resource allocations to certain processes are not possible. It is shown that the scheduler may introduce “artificial” deadlocks which Habermann's method does not prevent. Permanent blocking is the situation where certain processes never receive their resource requests. It is shown that deadlock prevention does not necessarily eliminate permanent blocking. A method of preventing permanent blocking is given.