#DEADLOCK IN OS SOFTWARE#

After that we calculate the resources available and take the resources requested by users as input and check for possibility of assigning the resources by taking counters if the resources requested by a particular person is less i.e.the resources on hold by employees based on the total number of resources available.We have used rand() to randomly distribute the resources among the employees.

#DEADLOCK IN OS SOFTWARE#

The software at that time randomly distributes the resources i.e.

They are requesting the use of resources at any given time which the administrator knows and enters it at as input to the software.

There are multiple instances of resources available in the office and there are 4 employees in the office using the resources.

We have simulated a software which is used to detect the deadlock in an office environment.The operator of the software is a resource administrator and checks for availability of resources based on the resources available at the current time.

Apply an algorithm to recover from the deadlock.

Apply an algorithm to examine the state of the system to determine whether a deadlock has occurred or not.

If a system does not employ either a deadlock prevention or deadlock avoidance algorithm then a deadlock situation may occur. Killing all processes will lead to inefficiency in the system because all the processes will execute again from starting. This is not a suggestible approach but can be implemented if the problem becomes very serious. Generally, the Operating system kills a process which has done the least amount of work until now. Killing a process can solve our problem but the bigger concern is toĭecide which process to kill. The moment we get into a deadlock, we will rollback all the allocations to get into the previous safe state. For this purpose, the OS needs to implement check pointing at every state. The operating system can rollback the system to the previous safe state. System passes through various states to get into the deadlock state. Well, choosing a resource which will be snatched is going to be a bit difficult. (process) and give it to the other process with the expectation that it will complete the execution and will release this resource sooner. We can snatch one of the resources from the owner of the resource In order to recover the system from deadlocks, either OS considers resources or processes.

Detection of the cycle is necessary but not sufficient condition for deadlock detection, in this case, the system may or may not be in deadlock depending on different situations.

If there are multiple instances of resources:.

In the above diagram, resource 1 and resource 2 have single instances.

Presence of cycle in the graph is the sufficient condition for deadlock.

In this case for Deadlock detection we can run an algorithm to check for cycles in the Resource Allocation Graph.For example, in the below diagram, Process 1 is holding Resource 1 and waiting for resource 2 which is acquired by process 2, and process 2 is waiting for resource 1. Similar situation occurs in operating systems when there are two or more processes holding some resources and waiting for resources held by other(s). A process in operating systems uses different resources and uses resources in the following way:ĭeadlock is a situation where a set of processes are blocked because each process is holding a resource and waiting for another resource acquired by some other process.Ĭonsider an example when two trains are coming toward each other on the same track and there is only one track, none of the trains can move once they are in front of each other.

Deadlock in os