Encyclopedia

Category: Operating System

  • Process Synchronization

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    Explanation:Process synchronization is a technique used in operating systems to coordinate the execution of concurrent processes, ensuring data consistency and preventing race conditions. Synchronization mechanisms are essential when multiple processes or threads access shared resources simultaneously. Common techniques include semaphores, mutexes, and monitors. The primary goals of process synchronization are mutual exclusion, progress, and bounded…

  • System Boot Process

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    Explanation:The system boot process involves a sequence of steps performed by a computer to initialize hardware components and load the operating system into memory. It starts with power-on, followed by the execution of the BIOS or UEFI firmware. The firmware conducts hardware checks through POST and identifies bootable devices to load the bootloader. The bootloader…

  • Device Driver

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    Explanation:A device driver is software that allows the operating system to communicate and control hardware components, such as printers, graphics cards, and storage devices. Device drivers act as a translator between hardware and the operating system, converting OS instructions into commands that hardware can execute. Operating systems include a variety of built-in drivers, but users…

  • BIOS (Basic Input/Output System)

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    Explanation:The BIOS is firmware embedded on a computer’s motherboard that initializes and tests hardware components during the boot process. It provides a software interface for the operating system to communicate with hardware devices. BIOS performs essential tasks like the Power-On Self Test (POST), identifying boot devices, and loading the operating system bootloader. Although BIOS has…

  • Booting

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    Explanation:Booting is the process of starting a computer and loading the operating system into memory. It begins when the computer is powered on and continues until the system is ready for user interaction. The boot process involves several stages, including hardware initialization, loading the bootloader, and transferring control to the operating system kernel. There are…

  • Shell

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    Explanation:A shell is a command-line interface (CLI) program that allows users to interact with the operating system by entering commands. It acts as an intermediary between the user and the OS kernel. Common tasks performed using a shell include file manipulation, program execution, and system configuration. Popular shell programs include Bash (Bourne Again Shell), Zsh,…

  • File Descriptor

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    Explanation:A file descriptor is an integer handle or reference used by an operating system to access files or I/O resources like sockets and pipes. When a process opens a file, the operating system assigns a file descriptor to track interactions with that file. In UNIX and UNIX-like operating systems, file descriptors 0, 1, and 2…

  • Virtual Machine

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    Explanation:A Virtual Machine (VM) is a software-based emulation of a physical computer that allows multiple operating systems to run on a single physical machine. It abstracts the underlying hardware and provides an isolated environment for applications. Virtual machines are managed by a hypervisor, which allocates system resources like CPU, memory, and storage to each virtual…

  • Round Robin Scheduling

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    Explanation:Round Robin (RR) is a preemptive CPU scheduling algorithm designed for time-sharing systems. Each process is assigned a fixed time quantum, and the processes are executed in a cyclic order. If a process does not complete within its allocated time, it is moved to the end of the queue. This algorithm ensures fairness and responsiveness…

  • LRU (Least Recently Used)

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    Explanation:LRU (Least Recently Used) is a page replacement algorithm used in operating systems to manage memory efficiently. When the system needs to replace a page in memory, LRU selects the page that has not been accessed for the longest period. LRU approximates the optimal page replacement strategy by tracking page usage over time. This algorithm…