# RISC OS

> computer operating system

**Wikidata**: [Q1202514](https://www.wikidata.org/wiki/Q1202514)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/RISC_OS)  
**Source**: https://4ort.xyz/entity/risc-os

## Summary  
RISC OS is a computer operating system originally developed by Acorn Computers in 1987, designed for ARM-based hardware. It was later maintained and evolved by companies including Castle Technology, RISCOS Ltd, and currently RISC OS Open. Known for its efficiency and modular design, RISC OS runs on platforms such as the Raspberry Pi and emulators like RPCEmu and Arculator.

## Key Facts  
- First released in **1987** by **Acorn Computers**  
- Currently developed by **RISC OS Open**, based in **Worthing, United Kingdom**  
- Latest stable version is **5.30**, released on **April 2, 2024**  
- Designed for **ARM architecture** and supports **Unix-like** environments  
- Replaced the **Arthur operating system** and was succeeded by **Galileo** (operating system)  
- Licensed as **freeware** but remains **copyrighted**  
- Runs on devices such as **Raspberry Pi** and under emulators like **RPCEmu** and **Arculator**  
- Supports browsers like **NetSurf** and **ELinks**

## FAQs  

### Q: What is RISC OS used for?  
A: RISC OS is used primarily on ARM-based computers, especially educational and hobbyist systems like the Raspberry Pi. It offers a lightweight, efficient environment for running applications and learning system internals.

### Q: Is RISC OS still in development?  
A: Yes, RISC OS is actively maintained by RISC OS Open, with the latest version being 5.30, released in April 2024.

### Q: Can RISC OS run on modern hardware?  
A: Yes, RISC OS can run on modern ARM hardware such as the Raspberry Pi and through various emulators like RPCEmu and Arculator on other operating systems.

### Q: Is RISC OS open source?  
A: While RISC OS is distributed as freeware, it is not fully open-source. Its source code is accessible under a permissive license, allowing redistribution but not necessarily modification.

### Q: How does RISC OS differ from Windows or macOS?  
A: RISC OS is lightweight, modular, and designed specifically for ARM processors. Unlike Windows or macOS, it originated in the 1980s and emphasizes simplicity and direct interaction with system components.

## Why It Matters  
RISC OS holds historical and technical significance as one of the earliest operating systems designed specifically for ARM architecture. Initially created to support Acorn Computers' RISC-based machines, it played a foundational role in the development of personal computing in the UK. Its modular design and efficiency influenced alternative approaches to operating system architecture. Today, RISC OS continues to serve educational and niche computing communities, particularly through its support of the Raspberry Pi and emulation platforms. Its longevity and adaptability make it a notable example of specialized OS design and community-driven software evolution.

## Notable For  
- Being one of the first operating systems designed for **ARM architecture**  
- Supporting **lightweight, modular system design** with built-in cooperative multitasking  
- Running natively on **Raspberry Pi** and popular emulators like **RPCEmu**  
- Maintaining active development decades after its initial release  
- Hosting a unique ecosystem of software including **NetSurf** and **ELinks**

## Body  

### Origins and Development  
RISC OS was originally developed by **Acorn Computers** in **1987** as the successor to the **Arthur operating system**. It was designed to leverage the performance of Acorn's new RISC-based processors. Over time, development transitioned through several entities, including **Castle Technology** and **RISCOS Ltd**, before being taken over by **RISC OS Open** in **2006**.

### Architecture and Design  
RISC OS is optimized for **ARM architecture** and features a modular kernel, allowing dynamic loading and unloading of system modules. The system uses the **Advanced Disc Filing System (ADFS)**, introduced in 1983, and supports cooperative multitasking. It has a lightweight footprint, making it suitable for embedded systems and older hardware.

### Current Status  
The latest stable version is **5.30**, released on **April 2, 2024**, and is available from [riscosopen.org](https://www.riscosopen.org). It is categorized as both an **operating system** and **open-source software** (under a freeware license), and supports modern platforms like the **Raspberry Pi**.

### Platforms and Compatibility  
RISC OS runs natively on:
- **Raspberry Pi** models
- Acorn’s RISC-based computers

It also operates via emulators such as:
- **RPCEmu**
- **Arculator**
- **ArcEm**

Browsers like **NetSurf** and **ELinks** provide internet access within the OS.

### Licensing and Distribution  
Although RISC OS is distributed as **freeware**, it is **not fully open-source**. Source code access is granted under a permissive license that allows redistribution but may restrict modification rights. The software remains **copyrighted**.

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## References

1. [Source](https://www.riscosopen.org/news/articles/2020/10/24/risc-os-5-28-now-available)
2. [2024](https://www.riscosopen.org/news/articles/2024/04/27/risc-os-5-30-now-available)
3. Freebase Data Dumps. 2013