RISC OS is a computer operating system originally developed by Acorn Computers Ltd in Cambridge, England for their range of desktop computers, based on their own ARM architecture. First released in 1987, under the name Arthur, the subsequent iteration was renamed as RISC OS 2.00 in 1988. The operating system takes its name from the RISC (Reduced Instruction Set Computing) architecture used on supported systems.From 1988 to 1998, RISC OS was bundled with nearly every ARM based Acorn computer model, including the Archimedes range of computers, and RiscPC and A7000 computers.After the breakup of Acorn in 1998, development of RISC OS was continued by several companies, including RISCOS Ltd and Castle Technology. Also since 1998, RISC OS has been bundled with a number of ARM-based Acorn Clone personal computers such as the Iyonix and A9home.Most recent stable versions run on either the Iyonix's ARMv5, Cortex-A8 ARMv7 processors such as that used in the BeagleBoard and Touch Book, or (natively on the RiscPC or under emulation) ARMv3/ARMv4. In 2011, a port for the Cortex-A9 PandaBoard was announced.