RISC Operating System

🧩 1. Basic Information

Field —>Description
OS Name —>RISC OS
Developer —>Originally Acorn Computers, now maintained by RISC OS Open Ltd (ROOL)
First Released —>1987 (as Arthur, then RISC OS 2 in 1988)
Latest Version —>RISC OS 5.29 (2024 community release)
License Type —>Mostly open source (castle license / shared source)
Supported Platforms —>ARM (Archimedes, Raspberry Pi, BeagleBoard, Iyonix PC)
Still Active? —>✅ Yes, with active enthusiasts & new builds

⚙️ 2. Kernel & Architecture

Kernel Type: Monolithic, highly optimized for ARM processors

Runs almost entirely in a single address space for speed — minimal memory protection

Supports preemptive multitasking of I/O, cooperative multitasking of applications

Designed for low RAM systems (originally 512 KB to 4 MB RAM)

🌟 3. Key Features

Icon bar desktop: unique WIMP GUI (Windows, Icons, Menus, Pointer) environment

Uses anti-aliased fonts, vector graphics long before Windows/Mac did

Modular system with applications often distributed as complete folders (called applications directories)

Very fast boot — direct to GUI in a second or two even on old hardware

Strong BBC BASIC integration — can edit/run BASIC directly from the desktop

Portable file types with filetype metadata, rather than extensions (.txt, .jpg, etc.)

📈 4. Version History & Important Milestones ✅

Version / Milestone —>Year —>Description
Arthur 1.2 —>1987 —>First shipped OS on Acorn Archimedes
RISC OS 2 —>1988 —>Stable release, set groundwork for GUI
RISC OS 3 —>1991–94 —>Improved multitasking, new Filer & icons
RISC OS 4 / 6 —>1999± –>Enhanced UI, larger file systems
RISC OS 5 —>2002± –>32-bit, open sourced, runs on Raspberry Pi & modern ARM boards
RISC OS Open (ROOL) —>2006± –>Community managed, frequent stable builds
2020s —>2024 —>RISC OS 5.29 release, continues with Pi 400, RK3399, Beagle boards

🎯 5. Target Audience & Use Cases

Retro enthusiasts: love it on vintage Acorn Archimedes or emulators

Education: was used across UK schools in the 90s

Embedded ARM developers: still used as a tiny desktop OS on Pi & small boards

BBC BASIC programmers: continuing strong integration with the OS

Hobbyists experimenting with fast ARM native systems without bloat

✅ 6. Pros & Cons

Pros —>Cons
Blazing fast on low-end hardware —>Cooperative multitasking can let apps hang the desktop
Unique, clean desktop interface —>Not compatible with modern Linux/Windows apps
Very small footprint, boots instantly —>Limited hardware support outside certain ARM devices
Still actively improved by ROOL & community —>Requires learning unique conventions (filers, filetypes)

🎨 7. UI Demo & Visuals

Boot straight to icon bar desktop, showing mounted drives & running apps

Open Filer windows browsing application directories

Open a BBC BASIC prompt inside the GUI, run small programs

Open Paint or Draw to show scalable vector graphics

Show config utilities (Display modes, Network settings) on a Raspberry Pi

📦 8. Ecosystem & App Support

Includes BBC BASIC, Draw (vector editor), Edit, Paint

Many classic apps ported: Impression (DTP), Ovation, ArtWorks

Still receives new ports via RISC OS Packaging Project (ROPkg)

Can browse the internet with NetSurf, run lightweight email clients, SSH tools

🔐 9. Security & Updates

Minimal OS design with low-level direct hardware control (reduces attack surface but no memory protection)

Updated by ROOL via quarterly Stable & Development builds

Packages often distributed as zip files containing entire applications — drag & drop to install

🌍 10. Community, License & Development

License: mixture of Castle’s shared source, BSD-style open source via ROOL

Maintained by RISC OS Open Ltd (ROOL) plus global contributors

Active forums (ROOL forums, StarDot retro computing) & developers on GitHub

New versions optimized for Raspberry Pi, PineBook, RK3399 boards