Deadlock
Deadlock is a problem that can exist when a group of processes compete for access to fixed resources.
Def: deadlock exists among a set of processes if every process is waiting for an event that can be caused only by another process in the set.
Example: two processes share 2 resources that they must request (before using) and release (after using). Request either gives access or causes the proc. to block until the resource is available.
Proc1: Proc2:
request tape request printer
request printer request tape
… <use them> … <use them>
release printer release tape
release tape release printer