operatingsystem

An operating system (OS) is system software that manages computer hardware and software resources and provides common services for computer programs. The OS acts as an intermediary between applications and hardware, enabling tasks such as running programs, accessing memory, and using input/output devices.

Key responsibilities include process management (scheduling, context switching, synchronization), memory management (allocation, virtual memory, protection), file systems (naming, storage, access control), device management (drivers for disks and peripherals), and security and protection (authentication and access control).

OS components include the kernel, system libraries, and user interfaces. The kernel operates in privileged mode and handles low-level resource management; user-space programs run with restricted privileges. Kernel architectures range from monolithic to microkernel and hybrids.

Common types include general-purpose desktop and server OSes, real-time operating systems (RTOS) for deterministic timing, embedded OSes for devices, and multi-user or single-user variants. Popular contemporary examples are Windows, macOS, Linux distributions, and various RTOS used in embedded systems.

Modern OSs provide graphical or command-line interfaces, support networking, virtualization, and cloud services, and are designed for multiprocessing, memory protection, and I/O scheduling. Core concepts include processes and threads, inter-process communication, deadlock, scheduling algorithms, memory hierarchies, and file system design. Understanding operating systems is foundational to computer science and software engineering.