RISC OS

RISC OS ( /rɪskoʊˈɛs/) is a series of graphical user interface-based computer operating systems (OSes) designed for ARM architecture systems. It takes its name from the RISC (reduced instruction set computing) architecture supported. The OS was originally developed by Acorn Computers for use with their 1987 range of Archimedes personal computers using the Acorn RISC Machine processors. It comprises a command-line interface and desktop environment with a windowing system.

From 1988 to 1998, the OS was bundled with nearly every ARM-based Acorn computer model, including the Archimedes range, RiscPC, NewsPad and A7000. A version of the OS (called NCOS) was used in Oracle's Network Computer and compatible systems. After the breakup of Acorn in 1998, development of the OS was forked and separately continued by several companies, including RISCOS Ltd, Pace Micro Technology and Castle Technology. Since 1998 it has been bundled with a number of ARM-based desktop computers such as the Iyonix and A9home. As of 2012, the OS remains forked and is independently developed by RISCOS Ltd and the RISC OS Open community.

Most recent stable versions run on the ARMv3/ARMv4 RiscPC (or under emulation via VirtualAcorn or RPCEmu), the ARMv5 Iyonix and ARMv7 Cortex-A8 processors (such as that used in the BeagleBoard and Touch Book). In 2011, a port for the Cortex-A9 PandaBoard was announced and a development version for the Raspberry Pi was seen in public.