About RISC OS

What's RISC OS?

RISC OS is the operating system developed for use on Acorn computers. The ‘RISC’ in the name refers to the architecture of the microprocessor used in Acorn's home computers and workstations - the ARM.

What's an ARM?

It initially stood for Acorn RISC Machine, but when the business was spun out of Acorn into ARM Limited, it was altered to Advanced RISC Machine. RISC is an abbreviation of Reduced Instruction Set Architecture and refers to the design philosophy of the processor.

Who are Acorn?

Acorn was a computer manufacturer that was based in Cambridge (UK). Famous for producing a range of computers for the BBC (the most famous of which is the BBC B), they later went on to design the ARM for the Archimedes range of machines. The ARM was also later used in the A series machines, and the last main Acorn range - the RiscPC.

Aside from a strong presence in UK schools, Acorn's innovative computers managed to develop a large following of home enthusiasts despite the lack of any market profile.

Acorn also produced other devices including a broadband set-top box, the original reference design for Oracle's Network Computer (NC), and an information appliance called the NewsPAD. Despite not bringing fortune to Acorn, similar designs from other manufacturers are finding success today.

Acorn technology is even involved in the control of satellites.

While Acorn does not exist as a single company anymore, its legacy lives on:

• The microprocessor spin-off - ARM - is now a market leader in embedded microprocessors. At the last count, three-quarters of the world's mobile telephones use ARM technology. ARM microprocessors are found in everything from routers to the Nintendo Gameboy Advance.
• The design and manufacture of Acorn compatible computers is being continued by at least three companies: Castle, RiscStation and Microdigital.
• Some ex-Acorn engineers formed Element 14 - a DSL technology consultancy that was subsequently bought for a large sum of money by Broadcom.
• Most of the other engineers where headhunted by Pace Micro Technology - a major designer and manufacturer of digital set-top boxes.
• The operating system itself is being developed by Pace Micro Technology. RISC OS Limited was created to develop and market the desktop version.

Screenshots

Web browser and some filer windows (236K)	Web browser (85K)	Menus (119K)
RISC OS 4 desktop (483K)	WindowsTM inside a window (144K)

Further reading

• Acorn Hardware and Operating Systems - what is an Acorn?
• RISC OS - an introduction by Acorn User
• RISC OS in action - reasons for choosing to use it
• Acorn or Wintel? - more reasons for choosing to use it
• An excellent page about Acorn computers and ARM processors - by Richard Atterer

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