Operating System

An operating system is system software that manages computer hardware, software resources, and provides common services for computer programs.

Managing hardware resources, providing a user interface, and executing and providing services for applications software.

The kernel is the core part of an OS, responsible for managing system resources, hardware, and communication between software and hardware.

A process is an independent program in execution with its own memory space, while a thread is the smallest unit of execution within a process, sharing the process's resources.

Multitasking is the ability of an OS to execute multiple tasks or processes simultaneously.

Virtual memory is a memory management technique that gives an application the impression it has contiguous working memory, while actually using physical memory fragments and possibly disk storage.

A system call is a request from a program to the operating system to perform a task that the program does not have direct permission to execute.

An interrupt is a signal to the processor emitted by hardware or software indicating an event that needs immediate attention.

Context switching is the process of storing the state of a process or thread and restoring the state of another, allowing multiple processes to share a single CPU resource.

A file system controls how data is stored and retrieved, managing files and directories on a storage device.

Device drivers are specialized programs that allow the operating system to communicate with hardware devices.

A deadlock is a situation in which two or more processes are unable to proceed because each is waiting for the other to release a resource.

Paging is a memory management scheme that eliminates the need for contiguous allocation of physical memory by dividing memory into fixed-sized pages.

A scheduler is a system component that decides which process runs at a given time, managing process execution order and CPU time.

User mode is a restricted processing mode for applications, while kernel mode has full access to hardware and system resources, used by the operating system's core components.

Swapping is the process of moving processes between main memory and a storage device to ensure that main memory is efficiently used.

An RTOS is designed to process data as it comes in, typically without buffering delays, suitable for applications requiring consistent, predictable response times.

A bootloader is a small program that initializes the operating system during the boot process of a computer.

Memory fragmentation is the condition of a memory system when most of the free memory is split into small, non-contiguous blocks, reducing efficiency.

A CLI allows users to interact with the operating system by typing commands into a text-based interface.

A Graphical User Interface (GUI) allows users to interact with the operating system through graphical elements like windows, icons, and menus.

Process synchronization is a mechanism to ensure that two or more processes do not execute certain parts of their program simultaneously to avoid conflicts.

A semaphore is a synchronization tool used to control access to a common resource in concurrent systems by multiple processes.

A critical section is a part of a program that accesses shared resources and must not be concurrently accessed by more than one thread or process.

A hypervisor is software that creates and manages virtual machines by allowing multiple operating systems to run concurrently on a single physical machine.

A task scheduler manages the execution of tasks, ensuring efficient CPU use by determining which task runs when and for how long.

Preemptive multitasking allows the OS to control process execution, interrupting processes, while non-preemptive multitasking relies on processes to voluntarily yield control.

Thrashing occurs when a system spends most of its time swapping pages in and out of memory rather than executing instructions, leading to low performance.

A shell is a user interface that provides access to various services of an operating system, typically through a command-line or graphical interface.