Skip to content
codingtube

codingtube

Coding and Programming tutorials

  • javascript
  • React
  • ES6
  • React js
  • coding
  • ffmpeg
  • java
  • programming
  • information
  • coding
  • Privacy Policy
  • Twitter trends
  • Age Calculatore
  • Codingtube Community
  • YouTube Tags Generator
  • About
  • Toggle search form

Scheduling Algorithms in operating System

Posted on December 16, 2021December 16, 2021 By christo No Comments on Scheduling Algorithms in operating System

CPU scheduling deals with the problem of deciding which of the processes in the ready queue is to be allocated the CPU. There are many different CPU-scheduling algorithms.

Table of Contents

  • First-Come, First-Served Scheduling
  • Shortest-Job-First Scheduling
  • Priority Scheduling
  • Round-Robin Scheduling

First-Come, First-Served Scheduling

By far the simplest CPU-scheduling algorithm is the first-come, first-served (FCFS) scheduling algorithm. With this scheme, the process that requests the CPU first is allocated the CPU first. The implementation of the FCFS policy is easily managed with a FIFO queue. When a process enters the ready queue, its PCB is linked onto the tail of the queue. When the CPU is free, it is allocated to the process at the head of the queue. The running process is then removed from the queue. The code for FCFS scheduling is simple to write and understand

Shortest-Job-First Scheduling

A different approach to CPU scheduling is the shortest-job-first(SJF) scheduling algorithm. This algorithm associates with each process the length of the process’s next CPU burst. When the CPU is available, it is assigned to the process that has the smallest next CPU burst. If the next CPU bursts of two processes are the same, FCFS scheduling is used to break the tie.

Note that a more appropriate term for this scheduling method would be the shortest-next CPU-burst algorithm, because scheduling depends on the length of the next CPU burst of a process, rather than its total length. We use the term SJF because most people and textbooks use this term to refer to this type of scheduling

Priority Scheduling

The SJF algorithm is a special case of the general priority-scheduling algorithm. A priority is associated with each process, and the CPUis allocated to the process with the highest priority. Equal-priority processes are scheduled in FCFS order. An SJF algorithm is simply a priority algorithm where the priority (p) is the inverse of the (predicted) next CPU burst. The larger the CPU burst, the lower the priority, and vice versa

Round-Robin Scheduling

The round-robin (RR) scheduling algorithm is designed especially for time sharing systems. It is similar to FCFS scheduling, but preemption is added to enable the system to switch between processes. A small unit of time, called a time quantum or time slice, is defined. A time quantum is generally from 10 to 100 milliseconds in length. The ready queue is treated as a circular queue The CPU scheduler goes around the ready queue, allocating the CPU to each process for a time interval of up to 1 time quantum.

To implement RR scheduling, we again treat the ready queue as a FIFO queue of processes. New processes are added to the tail of the ready queue. The CPU scheduler picks the first process from the ready queue, sets a timer to interrupt after 1 time quantum, and dispatches the process

One of two things will then happen. The process may have a CPU burst of less than 1 time quantum. In this case, the process itself will release the CPU voluntarily. The scheduler will then proceed to the next process in the ready queue. If the CPU burst of the currently running process is longer than 1 time quantum, the timer will go off and will cause an interrupt to the operating system. A context switch will be executed, and the process will be put at the tail of the ready queue. The CPU scheduler will then select the next process in the ready queue.

operating system Tags:Scheduling Algorithms in operating System

Post navigation

Previous Post: Scheduling Criteria in Operating Sytem
Next Post: Multilevel Queue Scheduling

Related Posts

Clocks and Timers in Operating System operating system
Contiguous Memory Allocation operating system
Synchronization in Solaris operating system
Pthreads in Operating System operating system
File-System Mounting in Operating System operating system
Computing Environments in operating System operating system

Leave a Reply Cancel reply

You must be logged in to post a comment.

Recent Posts

  • Affiliate Marketing Principles
  • The Basics You Need to Know About Affiliate Marketing
  • Affiliate Marketing Options
  • All About Affiliate Marketing
  • Classification of Database Management Systems
  • Three-Tier and n-Tier Architectures
    for Web Applications
  • Two-Tier Client/Server Architectures for DBMSs
  • Basic Client/Server Architectures in DBMS
  • Centralized DBMSs Architecture in DBMS
  • Tools, Application Environments, and Communications Facilities in DBMS

Categories

  • Affiliate marketing (5)
  • Algorithm (43)
  • amp (3)
  • android (223)
  • Android App (8)
  • Android app review (4)
  • android tutorial (60)
  • Artificial intelligence (61)
  • AWS (3)
  • bitcoin (8)
  • blockchain (1)
  • c (5)
  • c language (105)
  • cloud computing (4)
  • coding (4)
  • coding app (4)
  • complex number (1)
  • Computer Graphics (66)
  • data compression (65)
  • data structure (188)
  • DBMS (44)
  • digital marketing (9)
  • distributed systems (11)
  • ffmpeg (26)
  • game (3)
  • html (6)
  • image processing (35)
  • Inequalities (1)
  • information (4)
  • java (212)
  • java network (1)
  • javascript (9)
  • kotlin (4)
  • leetcode (1)
  • math (21)
  • maven (1)
  • mysql (1)
  • Node.js (8)
  • operating system (109)
  • php (310)
  • Principle Of Mathematical Induction (1)
  • programming (6)
  • Python (4)
  • Python data structure (9)
  • React native (1)
  • React.js (22)
  • Redux (1)
  • seo (4)
  • set (12)
  • trigonometry (6)
  • vue.js (35)
  • XML (3)

sitemap

sitemap of videos

sitemap of webstories

sitemap of website

  • Affiliate marketing
  • Algorithm
  • amp
  • android
  • Android App
  • Android app review
  • android tutorial
  • Artificial intelligence
  • AWS
  • bitcoin
  • blockchain
  • c
  • c language
  • cloud computing
  • coding
  • coding app
  • complex number
  • Computer Graphics
  • data compression
  • data structure
  • DBMS
  • digital marketing
  • distributed systems
  • ffmpeg
  • game
  • html
  • image processing
  • Inequalities
  • information
  • java
  • java network
  • javascript
  • kotlin
  • leetcode
  • math
  • maven
  • mysql
  • Node.js
  • operating system
  • php
  • Principle Of Mathematical Induction
  • programming
  • Python
  • Python data structure
  • React native
  • React.js
  • Redux
  • seo
  • set
  • trigonometry
  • vue.js
  • XML
  • Blog
  • Data compression tutorial - codingpoint
  • How to change mbstring in php 5.6
  • How to diagnose out of memory killed PHP-FPM
  • Introduction to jQuery
  • Privacy
  • Affiliate marketing
  • Algorithm
  • amp
  • android
  • Android App
  • Android app review
  • android tutorial
  • Artificial intelligence
  • AWS
  • bitcoin
  • blockchain
  • c
  • c language
  • cloud computing
  • coding
  • coding app
  • complex number
  • Computer Graphics
  • data compression
  • data structure
  • DBMS
  • digital marketing
  • distributed systems
  • ffmpeg
  • game
  • html
  • image processing
  • Inequalities
  • information
  • java
  • java network
  • javascript
  • kotlin
  • leetcode
  • math
  • maven
  • mysql
  • Node.js
  • operating system
  • php
  • Principle Of Mathematical Induction
  • programming
  • Python
  • Python data structure
  • React native
  • React.js
  • Redux
  • seo
  • set
  • trigonometry
  • vue.js
  • XML
  • Blog
  • Data compression tutorial - codingpoint
  • How to change mbstring in php 5.6
  • How to diagnose out of memory killed PHP-FPM
  • Introduction to jQuery
  • Privacy

© codingtube.tech