Operating System

Virtual Memory | Operating System

Virtual Memory is a storage allocation scheme in which secondary memory can be addressed as though it were part of main memory. The addresses a program may use to reference memory are distinguished from the addresses the memory system uses to identify physical storage sites, ...
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Operating Systems | Segmentation

A Memory Management technique in which memory is divided into variable sized chunks which can be allocated to processes. Each chunk is called a Segment. A table stores the information about all such segments and is called Segment Table. Segment Table: It maps two dimensional ...
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Operating System | Page Replacement Algorithms

In a operating systems that use paging for memory management, page replacement algorithm are needed to decide which page needed to be replaced when new page comes in. Whenever a new page is referred and not present in memory, page fault occurs and Operating System ...
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Operating System | Memory Management |Partition Allocation Method

In operating system, following are four common memory management techniques. Single contiguous allocation: Simplest allocation method used by MS-DOS. All memory (except some reserved for OS) is available to a process. Partitioned allocation: Memory is divided in different blocks Paged memory management: Memory is divided ...
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Deadlock Prevention And Avoidance

Deadlock Characteristics Deadlock has following characteristics. Mutual Exclusion. Hold and Wait. No preemption. Circular wait. Deadlock Prevention We can prevent Deadlock by eliminating any of the above four condition. Eliminate Mutual Exclusion It is not possible to dis-satisfy the mutual exclusion because some resources, such ...
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Disk Scheduling Algorithms

Disk scheduling is is done by operating systems to schedule I/O requests arriving for disk. Disk scheduling is also known as I/O scheduling. Disk scheduling is important because: Multiple I/O requests may arrive by different processes and only one I/O request can be served at ...
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File Systems | Operating System

A file is a collection of related information that is recorded on secondary storage. Or file is a collection of logically related entities. From user’s perspective a file is the smallest allotment of logical secondary storage. FILE DIRECTORIES: Collection of files is a file directory ...
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Deadlock Detection And Recovery

In the previous post, we have discussed Deadlock Prevention and Avoidance. In this post, Deadlock Detection and Recovery technique to handle deadlock is discussed. Deadlock Detection 1. If resources have single instance: In this case for Deadlock detection we can run an algorithm to check ...
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Operating System | Process Management | Deadlock Introduction

A process in operating systems uses different resources and uses resources in following way. 1) Requests a resource 2) Use the resource 2) Releases the resource Deadlock is a situation where a set of processes are blocked because each process is holding a resource and ...
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Operating System | Process Synchronization | Introduction

On the basis of synchronization, processes are categorized as one of the following two types: Independent Process : Execution of one process does not affects the execution of other processes. Cooperative Process : Execution of one process affects the execution of other processes. Process synchronization problem arises ...
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