Ready Queue

What is CPU Scheduling?

CPU scheduling is the OS mechanism that decides which ready process or thread gets to run on the CPU next, aiming to balance throughput, fairness, and responsi…

What Is Round Robin Scheduling?

Round robin scheduling is a preemptive CPU scheduling algorithm that gives every process a fixed time slice, called a quantum, in a cyclic order, so no single…

What is First-Come-First-Served (FCFS) Scheduling?

First-Come-First-Served (FCFS) is a non-preemptive CPU scheduling algorithm that runs processes strictly in the order they arrive in the ready queue, giving ea…

What is Multilevel Queue Scheduling?

Multilevel queue scheduling partitions the ready queue into several separate queues by process type — such as system, interactive, and batch — each with its ow…

What is Multilevel Feedback Queue Scheduling?

Multilevel feedback queue (MLFQ) scheduling uses several ready queues ranked by priority, each with its own time quantum, and moves a process between queues ba…

How Does Thread Scheduling Work?

Thread scheduling is the mechanism by which the OS (or a user-space runtime) decides which of the runnable threads gets CPU time next, typically driven by prio…

What are the Different Process States in an OS?

A process moves through a small set of states — new, ready, running, waiting (blocked), and terminated — and the OS scheduler transitions it between them based…

What is Turnaround Time in CPU Scheduling?

Turnaround time is the total time a process spends in the system, measured as completion time minus arrival time, and it includes waiting in the ready queue, e…

Waiting Time vs Response Time in Scheduling

Waiting time is the total time a process spends sitting in the ready queue without running, while response time is the time from when a process arrives until i…

What is Aging in CPU Scheduling?

Aging is a scheduling technique where the OS gradually increases the priority of a task the longer it waits in the ready queue, which guarantees that even a lo…

What is Load Balancing in a Multiprocessor OS?

Load balancing in a multiprocessor OS is the scheduler policy of spreading runnable tasks evenly across all available CPU cores so no core sits idle while anot…

What Are the Process Scheduling Queues in an OS?

An operating system tracks processes through several distinct scheduling queues — the job queue, the ready queue, and one or more device (I/O) queues — and a p…

Long-Term vs Short-Term Scheduler: What Is the Difference?

The long-term scheduler controls how many processes are admitted from the job queue into memory (the degree of multiprogramming) and runs infrequently, while t…