Operating System Tutorial Last Updated : 08 Jul, 2025 Comments Improve Suggest changes Like Article Like Report An Operating System(OS) is a software that manages and handles hardware and software resources of a computing device. Responsible for managing and controlling all the activities and sharing of computer resources among different running applications.A low-level Software that includes all the basic functions like processor management, memory management, file management, etc.It mainly acts a government for your system that has different departments to manage different resources.Examples are Linux, Unix, Windows 11, MS DOS, Android, macOS and iOS. Basics : IntroductionTypes of OSKernel in OSSystem Call System Initialization Process Scheduling : Process Introduction Process Table and Control Block Process Management Introduction Process SchedulerCPU Scheduling AlgorithmsPreemptive vs Non-Preemptive Dispatcher vs schedulerStarvation and Aging in Operating Systems >> Quiz on CPU Scheduling Process SynchronizationInter Process CommunicationIntroduction to Process Synchronization Critical SectionPeterson’s Algorithm in Process SynchronizationLock variable synchronization mechanismSemaphores in operating systemClassical IPC Problems Communication using signals in CMutex vs. SemaphoreMonitors for Process Synchronization Dekker’s algorithmBakery AlgorithmMutex lock for Linux Thread SynchronizationPriority Inversion >> Quiz on Process Management in OS Deadlock : Deadlock IntroductionDeadlock Prevention And AvoidanceDeadlock Detection And RecoveryBanker’s AlgorithmDeadlock, Starvation, and LivelockResource Allocation Graph (RAG)Methods of resource allocation Program for Deadlock free condition >> Quiz on Deadlock Multithreading: Operating System | ThreadThreads and its typesOperating System | User Level thread Vs Kernel Level threadProcess-based and Thread-based MultitaskingMulti threading modelsBenefits of MultithreadingOperating System | Remote Procedure call (RPC) Memory Management : Introduction to memory and memory unitsMemory Management in Operating SystemBuddy System: Memory allocation techniquePagingSegmentationVirtual MemoryMemory InterleavingOperating system based VirtualizationSwap SpacePage Fault HandlingMemory Segmentation in 8086 MicroprocessorProgram for Next Fit algorithm in Memory ManagementOverlays in Memory ManagementBelady’s AnomalyPage Replacement Algorithms Second Chance (or Clock) Page Replacement PolicyAllocating kernel memory (buddy system and slab system)Static and Dynamic Libraries | Set 1Working with Shared Libraries | Set 1Named Pipe or FIFO with example C programTracing memory usage in Linux >> Quiz on Memory Management Disk Management: File SystemsUnix File SystemImplementing Directory Management using Shell ScriptFile Directory | Path NameStructures of DirectoryFile Allocation MethodsFile Access MethodsSecondary memorySecondary memory – Hard disk driveDisk Scheduling AlgorithmsProgram for SSTF disk scheduling algorithmWhat exactly Spooling is all about?Difference between Spooling and BufferingFree space management >> Quiz on Input Output Systems Misc Computer Memory Introduction to UNIX System MicrokernelKernel I/O Subsystem (I/O System)Important Linux Commands (leave, diff, cal, ncal, locate and ln)Process states and Transitions in a UNIX ProcessIntroduction to Linux Shell and Shell Scripting‘crontab’ in Linux with Examples Real time systemsTasks in Real Time systemsMonolithic Kernel and key differences from Microkernel Get/Set process resource limits in CDual Mode operations in OS Types of Operating System Batch OS (e.g. Transactions Process, Payroll System, etc.)Multi-programmed OS(e.g. Windows, UNIX, macOS, etc.)Timesharing OS(e.g. Multics, Linux, etc.)Real-Time OS(e.g. PSOS, VRTX, etc.)Distributed OS(e.g. LOCUS, Solaris, etc.) Operating System Functions Memory and processor ManagementNetwork ManagementSecurity ManagementFile ManagementError DetectionJob AccountingLast Minute Notes (LMNs) | Operating SystemsCommonly Asked Operating Systems Interview Questions‘Quizzes’ on Operating Systems !‘Practice Problems’ on Operating Systems ! Introduction to Operating System Visit Course Introduction to Operating System Types of Operating System Multithreading Introduction OS - Thread vs Process Difference between User Threads and Kernel Threads Comment More infoAdvertise with us Next Article What is an Operating System? K kartik Follow Improve Article Tags : Operating Systems GATE CS Similar Reads Operating System Tutorial An Operating System(OS) is a software that manages and handles hardware and software resources of a computing device. Responsible for managing and controlling all the activities and sharing of computer resources among different running applications.A low-level Software that includes all the basic fu 4 min read OS BasicsWhat is an Operating System?An Operating System is a System software that manages all the resources of the computing device. Acts as an interface between the software and different parts of the computer or the computer hardware. Manages the overall resources and operations of the computer. Controls and monitors the execution o 9 min read Types of Operating SystemsOperating Systems can be categorized according to different criteria like whether an operating system is for mobile devices (examples Android and iOS) or desktop (examples Windows and Linux). Here, we are going to classify based on functionalities an operating system provides.8 Main Operating System 11 min read Commonly Used Operating SystemThere are various types of Operating Systems used throughout the world and this depends mainly on the type of operations performed. These Operating Systems are manufactured by large multinational companies like Microsoft, Apple, etc. Let's look at the few most commonly used OS in the real world: Win 9 min read Operating System ServicesAn operating system is software that acts as an intermediary between the user and computer hardware. It is a program with the help of which we are able to run various applications. It is the one program that is running all the time. Every computer must have an operating system to smoothly execute ot 6 min read Operating Systems StructuresThe operating system can be implemented with the help of various structures. The structure of the OS depends mainly on how the various standard components of the operating system are interconnected and merge into the kernel. This article discusses a variety of operating system implementation structu 8 min read Booting and Dual Booting of Operating SystemWhen a computer or any other computing device is in a powerless state, its operating system remains stored in secondary storage like a hard disk or SSD. But, when the computer is started, the operating system must be present in the main memory or RAM of the system.What is Booting?When a computer sys 7 min read Introduction of System CallA system call is a programmatic way in which a computer program requests a service from the kernel of the operating system on which it is executed. A system call is a way for programs to interact with the operating system. A computer program makes a system call when it requests the operating system' 11 min read Process & ThreadsIntroduction of Process ManagementProcess Management for a single tasking or batch processing system is easy as only one process is active at a time. With multiple processes (multiprogramming or multitasking) being active, the process management becomes complex as a CPU needs to be efficiently utilized by multiple processes. Multipl 8 min read Process Table and Process Control Block (PCB)While creating a process, the operating system performs several operations. To identify the processes, it assigns a process identification number (PID) to each process. As the operating system supports multi-programming, it needs to keep track of all the processes. For this task, the process control 6 min read Process Schedulers in Operating SystemA process is the instance of a computer program in execution. Scheduling is important in operating systems with multiprogramming as multiple processes might be eligible for running at a time.One of the key responsibilities of an Operating System (OS) is to decide which programs will execute on the C 7 min read Context Switching in Operating SystemContext Switching in an operating system is a critical function that allows the CPU to efficiently manage multiple processes. By saving the state of a currently active process and loading the state of another, the system can handle various tasks simultaneously without losing progress. This switching 4 min read Thread in Operating SystemA thread is a single sequence stream within a process. Threads are also called lightweight processes as they possess some of the properties of processes. Each thread belongs to exactly one process.In an operating system that supports multithreading, the process can consist of many threads. But threa 7 min read CPU SchedulingCPU Scheduling in Operating SystemsCPU scheduling is a process used by the operating system to decide which task or process gets to use the CPU at a particular time. This is important because a CPU can only handle one task at a time, but there are usually many tasks that need to be processed. The following are different purposes of a 8 min read Preemptive and Non-Preemptive SchedulingIn operating systems, scheduling is the method by which processes are given access the CPU. Efficient scheduling is essential for optimal system performance and user experience. There are two primary types of CPU scheduling: preemptive and non-preemptive. Understanding the differences between preemp 5 min read Multiple-Processor Scheduling in Operating SystemIn multiple-processor scheduling multiple CPUs are available and hence Load Sharing becomes possible. However multiple processor scheduling is more complex as compared to single processor scheduling. In multiple processor scheduling, there are cases when the processors are identical i.e. HOMOGENEOUS 8 min read Thread SchedulingThere is a component in Java that basically decides which thread should execute or get a resource in the operating system. Scheduling of threads involves two boundary scheduling. Scheduling of user-level threads (ULT) to kernel-level threads (KLT) via lightweight process (LWP) by the application dev 7 min read DeadlockIntroduction of Deadlock in Operating SystemA deadlock is a situation where a set of processes is blocked because each process is holding a resource and waiting for another resource acquired by some other process. In this article, we will discuss deadlock, its necessary conditions, etc. in detail.Deadlock is a situation in computing where two 11 min read Banker's Algorithm in Operating SystemBanker's Algorithm is a resource allocation and deadlock avoidance algorithm used in operating systems. It ensures that a system remains in a safe state by carefully allocating resources to processes while avoiding unsafe states that could lead to deadlocks.The Banker's Algorithm is a smart way for 8 min read Wait For Graph Deadlock Detection in Distributed SystemDeadlocks are a fundamental problem in distributed systems. A process may request resources in any order and a process can request resources while holding others. A Deadlock is a situation where a set of processes are blocked as each process in a Distributed system is holding some resources and that 5 min read Deadlock Prevention And AvoidanceDeadlock prevention and avoidance are strategies used in computer systems to ensure that different processes can run smoothly without getting stuck waiting for each other forever. Think of it like a traffic system where cars (processes) must move through intersections (resources) without getting int 5 min read Deadlock Detection And RecoveryDeadlock Detection and Recovery is the mechanism of detecting and resolving deadlocks in an operating system. In operating systems, deadlock recovery is important to keep everything running smoothly. A deadlock occurs when two or more processes are blocked, waiting for each other to release the reso 6 min read Deadlock Ignorance in Operating SystemIn this article we will study in brief about what is Deadlock followed by Deadlock Ignorance in Operating System. What is Deadlock? If each process in the set of processes is waiting for an event that only another process in the set can cause it is actually referred as called Deadlock. In other word 5 min read Memory & Disk ManagementMemory Management in Operating SystemMemory is a hardware component that stores data, instructions and information temporarily or permanently for processing. It consists of an array of bytes or words, each with a unique address. Memory holds both input data and program instructions needed for the CPU to execute tasks.Memory works close 7 min read Fixed (or static) Partitioning in Operating SystemFixed partitioning, also known as static partitioning, is one of the earliest memory management techniques used in operating systems. In this method, the main memory is divided into a fixed number of partitions at system startup, and each partition is allocated to a process. These partitions remain 8 min read Variable (or Dynamic) Partitioning in Operating SystemIn operating systems, Memory Management is the function responsible for allocating and managing a computer’s main memory. The memory Management function keeps track of the status of each memory location, either allocated or free to ensure effective and efficient use of Primary Memory. Below are Memo 4 min read Paging in Operating SystemPaging is the process of moving parts of a program, called pages, from secondary storage (like a hard drive) into the main memory (RAM). The main idea behind paging is to break a program into smaller fixed-size blocks called pages.To keep track of where each page is stored in memory, the operating s 8 min read Segmentation in Operating SystemA process is divided into Segments. The chunks that a program is divided into which are not necessarily all of the exact sizes are called segments. Segmentation gives the user's view of the process which paging does not provide. Here the user's view is mapped to physical memory. Types of Segmentatio 4 min read Segmentation in Operating SystemA process is divided into Segments. The chunks that a program is divided into which are not necessarily all of the exact sizes are called segments. Segmentation gives the user's view of the process which paging does not provide. Here the user's view is mapped to physical memory. Types of Segmentatio 4 min read Page Replacement Algorithms in Operating SystemsIn an operating system that uses paging for memory management, a page replacement algorithm is needed to decide which page needs to be replaced when a new page comes in. Page replacement becomes necessary when a page fault occurs and no free page frames are in memory. in this article, we will discus 7 min read File Systems in Operating SystemA computer file is defined as a medium used for saving and managing data in the computer system. The data stored in the computer system is completely in digital format, although there can be various types of files that help us to store the data.File systems are a crucial part of any operating system 8 min read File Systems in Operating SystemA computer file is defined as a medium used for saving and managing data in the computer system. The data stored in the computer system is completely in digital format, although there can be various types of files that help us to store the data.File systems are a crucial part of any operating system 8 min read Advanced OSMultithreading in Operating SystemA thread is a path that is followed during a program’s execution. The majority of programs written nowadays run as a single thread. For example, a program is not capable of reading keystrokes while making drawings. These tasks cannot be executed by the program at the same time. This problem can be s 7 min read Compaction in Operating SystemCompaction is a technique to collect all the free memory present in the form of fragments into one large chunk of free memory, which can be used to run other processes. It does that by moving all the processes towards one end of the memory and all the available free space towards the other end of th 3 min read Belady's Anomaly in Page Replacement AlgorithmsBelady's Anomaly is a phenomenon in operating systems where increasing the number of page frames in memory leads to an increase in the number of page faults for certain page replacement algorithms. Normally, as more page frames are available, the operating system has more flexibility to keep the nec 11 min read Techniques to handle ThrashingPrerequisite - Virtual Memory Thrashing is a condition or a situation when the system is spending a major portion of its time servicing the page faults, but the actual processing done is very negligible. Causes of thrashing:High degree of multiprogramming.Lack of frames.Page replacement policy.Thras 6 min read Free Space Management in Operating SystemFree space management is a critical aspect of operating systems as it involves managing the available storage space on the hard disk or other secondary storage devices. The operating system uses various techniques to manage free space and optimize the use of storage devices. Here are some of the com 7 min read RAID (Redundant Arrays of Independent Disks)RAID (Redundant Arrays of Independent Disks) is a technique that makes use of a combination of multiple disks for storing the data instead of using a single disk for increased performance, data redundancy, or to protect data in the case of a drive failure. The term was defined by David Patterson, Ga 15 min read PracticeLast Minute Notes – Operating SystemsAn Operating System (OS) is a system software that manages computer hardware, software resources, and provides common services for computer programs. It acts as an interface between the user and the computer hardware.Table of Content Types of Operating System (OS): ThreadsProcessCPU Scheduling Algor 15+ min read Operating System Interview QuestionsAn operating system acts as a GUI between the user and the computer system. In other words, an OS acts as an intermediary between the user and the computer hardware, managing resources such as memory, processing power, and input/output operations. Here some examples of popular operating systems incl 15+ min read Operating Systems - GATE CSE Previous Year QuestionsThe Operating System(OS) subject has high importance in GATE CSE exam because:large number of questions nearly 10-12% of the total asked significant weightage (9-11 marks) across multiple years which can also be seen in the below given table:YearApprox. Marks from OSNumber of QuestionsDifficulty Lev 2 min read Like