GATE CS CPU Scheduling questions

The maximum number of processes that can be in $\textit{Ready}$ state for a computer system with $n$ CPUs is :

Consider the following set of processes that need to be scheduled on a single CPU. All the times are given in milliseconds. …

Three processes $A$, $B$ and $C$ each execute a loop of $100$ iterations. In each iteration of the loop, a process performs a single computation that requires $t_c$ CPU milliseconds and then initiates a single I/O operation that lasts for $t_{io}$ milliseconds. It is assumed that the computer where the processes execute has sufficient number of …

An operating system uses shortest remaining time first scheduling algorithm for pre-emptive scheduling of processes. Consider the following set of processes with their arrival times and CPU burst times (in milliseconds): …

A scheduling algorithm assigns priority proportional to the waiting time of a process. Every process starts with zero (the lowest priority). The scheduler re-evaluates the process priorities every $T$ time units and decides the next process to schedule. Which one of the following is TRUE if the processes have no I/O operations and all arrive at time zero?

Consider the $3$ processes, $P1, P2$ and $P3$ shown in the table. $$\small \begin{array}{|c|c|c|} \hline \textbf{Process} & \textbf{Arrival Time} & \textbf{Time Units Required} \\ \hline \text{P1} & 0 & 5\\ \hline \text{P2} & 1 & 7 \\ \hline \text{P3} & 3 & 4 \\ \hline \end{array}$$The completion order of the $3$ …

Which of the following statements are true? Shortest remaining time first scheduling may cause starvation Preemptive scheduling may cause starvation Round robin is better than FCFS in terms of response time

In the following process state transition diagram for a uniprocessor system, assume that there are always some processes in the ready state: Now consider the following statements: If a process makes a transition $D$, it would result in another process making transition $A$ immediately. A process $P_2$ in blocked state can make transition E while …

An operating system used Shortest Remaining System Time first (SRT) process scheduling algorithm. Consider the arrival times and execution times for the following processes: …

Group 1 contains some CPU scheduling algorithms and Group 2 contains some applications. Match entries in Group 1 to entries in Group 2. …

Consider three processes, all arriving at time zero, with total execution time of $10$, $20$ and $30$ units, respectively. Each process spends the first $\text{20\%}$ of execution time doing I/O, the next $\text{70\%}$ of time doing computation, and the last $\text{10\%}$ of time doing I/O again. The operating system uses a shortest remaining …

Consider three processes (process id $0$, $1$, $2$ respectively) with compute time bursts $2$, $4$ and $8$ time units. All processes arrive at time zero. Consider the longest remaining time first (LRTF) scheduling algorithm. In LRTF ties are broken by giving priority to the process with the lowest process id. The average turn around time is:

Consider three CPU-intensive processes, which require $10$, $20$ and $30$ time units and arrive at times $0$, $2$ and $6$, respectively. How many context switches are needed if the operating system implements a shortest remaining time first scheduling algorithm? Do not count the context switches at time zero and at the end.

Consider the following set of processes, with the arrival times and the CPU-burst times gives in milliseconds. …

A uni-processor computer system only has two processes, both of which alternate $10$ $\text{ms}$ CPU bursts with $90$ $\text{ms}$ I/O bursts. Both the processes were created at nearly the same time. The I/O of both processes can proceed in parallel. Which of the following scheduling strategies will result in the least CPU utilization (over a long …

Which of the following scheduling algorithms is non-preemptive?

In a computer system where the ‘best-fit’ algorithm is used for allocating ‘jobs’ to ‘memory partitions’, the following situation was encountered: …

Consider $n$ processes sharing the CPU in a round-robin fashion. Assuming that each process switch takes $s$ seconds, what must be the quantum size $q$ such that the overhead resulting from process switching is minimized but at the same time each process is guaranteed to get its turn at the CPU at least every $t$ seconds?

Four jobs to be executed on a single processor system arrive at time $0$ in the order $A, B, C, D$. Their burst CPU time requirements are $4, 1, 8, 1$ time units respectively. The completion time of $A$ under round robin scheduling with time slice of one time unit is

The sequence __________ is an optimal non-preemptive scheduling sequence for the following jobs which leaves the CPU idle for ________ unit(s) of time. …