Answer to Question #52527 in Programming & Computer Science for biruk

Question

State the recovery methods after the deadlock is defected.

Answer 1

Answer on Question

Statethe recovery methods after the deadlock is defected.

Solution:

Thereare three basic approaches to recovery from deadlock:
1. Inform the system operator,and allow him/her to take manual intervention.
2. Terminate one or moreprocesses involved in the deadlock
3. Preempt resources.

ProcessTermination:

Twobasic approaches, both of which recover resources allocated to terminated
processes:
· Terminateall processes involved in the deadlock. This definitely solves the deadlock,
but at the expense of terminating more processes than would be absolutely
necessary.
· Terminateprocesses one by one until the deadlock is broken. This is more conservative,
but requires doing deadlock detection after each step.

ResourcePreemption:

Whenpreempting resources to relieve deadlock, there are three important issues to
be addressed:
· Selectinga victim - Deciding which resources to preempt from which processes involves
many of the same decision criteria outlined above.
· Rollback- Ideally one would like to roll back a preempted process to a safe state prior
to the point at which that resource was originally allocated to the process.
Unfortunately it can be difficult or impossible to determine what such a safe
state is, and so the only safe rollback is to roll back all the way back to the
beginning.