Operating Systems
Understand what an operating system does, how it manages hardware, and the differences between major OS families.
What is an Operating System?
An Operating System (OS) is system software that manages computer hardware and software resources and provides common services for computer programs. Without an OS, you'd have to directly program the hardware for every task.
Core Functions of an OS
- Process Management — Scheduling and running multiple programs simultaneously.
- Memory Management — Allocating and freeing RAM for each running program.
- File System Management — Organizing files and directories on storage devices.
- Device Management — Communicating with hardware via drivers (keyboard, mouse, printer).
- Security & Access Control — Managing user accounts, permissions, and authentication.
- Networking — Handling network connections and data transfer protocols.
Major Operating Systems
- Windows — Dominant in personal computing. Easy to use, wide software support.
- macOS — Apple's OS for Mac computers. Known for stability and design.
- Linux — Open-source, used widely for servers, developers, and embedded systems.
- Android — Linux-based OS dominating the smartphone market.
- iOS — Apple's mobile OS, known for security and smooth performance.
Kernel: The Heart of an OS
The kernel is the core component of an OS that has complete control over everything in the system. It handles low-level tasks like managing CPU time and memory. Applications communicate with the kernel through system calls.
The kernel is to the OS what the CPU is to a computer — the fundamental engine everything else depends on.
Processes & Threads
- A process is an instance of a running program with its own memory space.
- A thread is a smaller unit of execution within a process — multiple threads share the same memory.
- Multitasking allows multiple processes to run "simultaneously" by rapidly switching between them.
What's Next?
Continue to Data Structures to learn how programs store and organize data, or explore Computer Networks to see how operating systems communicate across devices.