Comments on Prevention of System Deadlocks
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.
CACM January, 1971
Holt, R. C.
