RISC OS

RISC OS () is an operating system designed to run on ARM computers. Originally designed in 1987 by Acorn Computers of England, it was made for use in its new line of ARM-based Archimedes personal computers and was then shipped with other computers produced by the company. Despite the demise of Acorn, RISC OS continues to be developed today by the RISC OS Open community on version 5.0 of the system that was open sourced in 2018. RISC OS is a modular operating system and takes its name from the reduced instruction set computer (RISC) architecture it supports. It incorporates a graphical user interface and a windowing system. Between 1987 and 1998, RISC OS shipped with every ARM-based Acorn computer including the Archimedes line, Acorn's R line (with RISC iX as a dual-boot option), RiscPC, A7000, and prototype models such as the Acorn NewsPad and Phoebe computer. A version of the OS, named NCOS, was used in Oracle's Network Computer and compatible systems. After the break-up of Acorn, development of the OS was forked and continued separately by several companies, including RISCOS Ltd, Pace Micro Technology, Castle Technology, and RISC OS Developments. Since then, it has been bundled with several ARM-based desktop computers such as the Iyonix PC and A9home. Most recent stable versions run on the ARMv3/ARMv4 RiscPC, the ARMv5 Iyonix, ARMv7 Cortex-A8 processors and Cortex-A9 processors and the low-cost educational Raspberry Pi series of computers, with the exception of the Raspberry Pi 5.