The Acorn Archimedes was Acorn Computers’ first general purpose home computer to be based on their own ARM architecture.

Using a RISC design with a 32-bit CPU, at its launch in June 1987, the Archimedes was stated as running at 4 MIPS, with a claim of 18 MIPS during tests. The name is commonly used to describe any of Acorn’s contemporary designs based on the same architecture, even where Acorn did not include Archimedes in the official name.

The first models were released in June 1987, as the 300 and 400 series. The 400 series included 4 expansion slots (although a 2 slot backplane could be added to the 300 series as an official upgrade, and third parties produced their own 4 slot backplanes) and an ST506 controller for an internal hard drive. Both models included the Arthur operating system operating system (later replaced by RISC OS as a paid-for upgrade), BBC BASIC programming language and an emulator for Acorn’s earlier BBC Micro, and were mounted in two-part cases with a small central unit, monitor on top, and a separate keyboard and three-button mouse. All models featured onboard 8 channel stereo sound and were capable of displaying 256 colours on screen.

Four models were initially released with different amounts of memory, the A305, A310, A410 and A440. The 540 was unveiled in September 1990, and included higher speed SCSI and provision for connecting Genlock devices. The 300 and 400 were followed by a number of machines with minor changes and upgrades.

The Archimedes was one of the most powerful home computers available during the late 1980s and early 1990s; its main CPU was faster than the 68000 microprocessors found in the more popular Commodore Amiga and Atari ST machines. An 8 MHz 68000 had an average performance of roughly 1 MIPS for 16-bit workloads and 0.5 MIPS for 32-bit workloads, with peak performance of 2 MIPS for simpler 16-bit instructions. The 8 MHz ARM2 yielded 4.5 – 4.8 MIPS for 32-bit workloads in repeatable benchmark tests. (The Archimedes did not have the custom graphics chips that the Amiga did, however, such as the “Fat Agnus” chip with its powerful bit blitter that made the Amiga very fast at bitmap manipulation; the Archimedes outperformed the Amiga easily for 3D applications but the Amiga retained an edge in 2D.) The computer was exhibited at the 1987 Personal Computer World Show, along with Amigas, Atari STs and video game consoles. Commenting on the show, Crash magazine reported that “despite whiz-bang demos of Acorn’s Archimedes” the 8-bit machines were not dead.

The Archimedes won significant market share in the education markets of the UK, Ireland, Australia and New Zealand; the success of the Archimedes in British schools was due partly to its predecessor the BBC Micro and later to the Computers for Schools scheme organised by the Tesco supermarket chain in association with Acorn, and most students and pupils in these countries in the early 90s were exposed to an Archimedes or A-series computer. The Archimedes range was available in the US and Canada via Olivetti Canada. Despite a technical edge[citation needed], the Archimedes only ever met a moderate success beyond the education sector, becoming a ‘minority’ platform outside of certain niche markets.

By the early 1990s, the UK educational market began to turn away from the Archimedes. Apple Macintosh computers or IBM compatible PCs eclipsed the Archimedes in their multimedia capabilities, which led to an erosion of the Archimedes market share. The Tesco Computers for Schools scheme later changed partnership from Acorn to RM plc and many other computer-related suppliers, which also led to the decrease of the Archimedes’ educational market share.

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