What Is an Operating System

Short answer

An operating system manages hardware resources and provides services for applications. It handles process scheduling, memory allocation, file systems, and input/output.

How it works

The kernel is the core of the OS. It runs in privileged mode, arbitrating access to CPU time, RAM, and devices. User applications request resources through system calls.

Example

When you open a text editor, the OS allocates memory, schedules CPU time, and mediates keyboard input and screen output.

Why it matters

Without an operating system, every application would need to implement hardware drivers and resource management. The OS provides a stable, secure platform for software.