RISC OS
is a computer
operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs.
Time-sharing operating systems scheduler (computing), schedule tasks for ef ...
originally designed by
Acorn Computers
Acorn Computers Ltd. was a British computer company established in Cambridge, England, in 1978. The company produced a number of computers which were especially popular in the United Kingdom, UK, including the Acorn Electron and the Acorn Archi ...
Ltd in
Cambridge
Cambridge ( ) is a university city and the county town in Cambridgeshire, England. It is located on the River Cam approximately north of London. As of the 2021 United Kingdom census, the population of Cambridge was 145,700. Cambridge beca ...
, England. First released in 1987, it was designed to run on the
ARM chipset, which Acorn had designed concurrently for use in its new line of
Archimedes
Archimedes of Syracuse (;; ) was a Greek mathematician, physicist, engineer, astronomer, and inventor from the ancient city of Syracuse in Sicily. Although few details of his life are known, he is regarded as one of the leading scienti ...
personal computers. RISC OS takes its name from the
reduced instruction set computer (RISC) architecture it supports.
Between 1987 and 1998, RISC OS was included in every ARM-based Acorn computer model, including the Acorn 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 Corporation
Oracle Corporation is an American multinational computer technology corporation headquartered in Austin, Texas. In 2020, Oracle was the third-largest software company in the world by revenue and market capitalization. The company sells da ...
's
Network Computer and compatible systems.
After the break-up of Acorn in 1998, development of the OS was
forked and continued separately by several companies, including ,