GATEverse — GATE CSE previous year questions

An operating system handles requests to resources as follows. A process (which asks for some resources, uses them for some time and then exits the system) is assigned a unique timestamp are when it starts. The timestamps are monotonically increasing with time. Let us denote the timestamp of a process $P$ by $TS(P)$ . When a process $P$ requests for a resource the $OS$ does the following: When a process releases a resource, the process with the smallest timestamp (if any) amongst those waiting for the resource is awarded the resource. Can a deadlock over arise? If yes, show how. If not prove it. Can a process P ever starve? If yes, show how. If not prove it.

(A)

If no other process is currently holding the resource, the $OS$ awards the resource to $P$ .

(B)

If some process $Q$ with $TS(Q) < TS(P)$ is holding the resource, the $OS$ makes $P$ wait for the resources.

(C)

If some process $Q$ with $TS(Q)>TS(P)$ is holding the resource, the $OS$ restarts $Q$ and awards the resources to $P$ . (Restarting means taking back the resources held by a process, killing it and starting it again with the same timestamp)