Acorn Archimedes

The Acorn Archimedes was Acorn Computers Ltd's first general purpose home computer based on their own 32-bit ARM RISC CPU, and spawned a family of very capable machines with various options.

Contents

1 Description; Early models 2 The A3000 and A5000 3 A new range and a laptop 4 Significance and impact 5 See also 6 External links

Description; Early models

The first models were released in June 1987, as the 300 and 400 series. The machines differed primarily in that the 400 series included more expansion slots (four instead of two) and a ST506 controller for an internal hard drive. Both models included the Arthur OS (later versions to be called RISC OS, see below), BBC BASIC 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.

Four models were initially released with different amounts of memory, the A305, A310, A410 and A440. The 300 and 400 were followed by a number of machines with minor changes and upgrades:

• (A500 - 4 MB RAM, Archimedes development machine, never sold [1] (http://www.drobe.co.uk/riscos/artifact476.html))
• A305 - 512 KB RAM
• A310 - 1 MB RAM
• A410 - 1 MB RAM
• A420 - 2 MB RAM, 20 MB hard disk
• A440 - 4 MB RAM, 40 MB hard disk
• (A4xx/1 editions with improved memory controller)
• A540 - 4 MB RAM, 100 MB hard Disk
• (A680 and M4 - 8 MB RAM, RISCiX development machines, never sold)
• R140 - 4 MB RAM,   52 MB hard disk, RISCiX UNIX workstation
• R260 - 8 MB RAM, 100 MB hard disk, RISCiX UNIX workstation
• R225 - 4 MB RAM, RISCiX UNIX network computer

The A3000 and A5000

Work began on a successor to the Arthur OS, initially named Arthur 2, but with the release of the Hollywood movie (http://www.imdb.com/title/tt0094678/) of the same name the it was renamed to RISC OS 2. Along with it, a number of new machines were introduced as well, and in May 1989 the 300 series was phased out in favor of the new Acorn A3000.

Unlike the previous Archimedes models, the A3000 came in a single-part case similar to the Amiga 500 and Atari ST computers, with the keyboard attached to the main unit. This kind of housing consumes a lot of desktop space, a problem that Acorn tried to overcome by offering a monitor stand that could be attached to the base unit. The new model only sported a single expansion slot. Unlike the 300 series, the 400 series was kept in production.

The other new model, the A5000, came in a newly designed two-part case that looked more conventional than the housings of its predecessors. It featured the new 25 MHz ARM3 processor, while the A3000 was still equipped with an 8 MHz ARM2. The A3000 ran RISC OS 2, while the A5000 ran the new RISC OS 3.0. It came with 4 MB of RAM, compared to the A3000's 1 MB, and featured either a 40 MB or an 80 MB hard drive. A later version of the A5000 was available, featuring a 33 MHz ARM3, 2 or 4 MB of RAM and an 80 or 120 MB hard drive.

A new range and a laptop

In 1991, a new range was produced, using the ARM250 microcontroller, an ARM2 processor with integrated memory and video controllers, performing better thanks to an increase in clock frequency, and running RISC OS 3.1. The A30x0 series had a one-piece design, similar to the A3000, while the A4000 looked like a slightly slimmer A5000. The A3010 model was intended to be a home computing machine, featuring a TV modulator and joystick ports, while the A3020 targeted the home office and educational markets, featuring a built-in 2.5" hard drive. Technically, the A4000 was almost identical to the A3020, only differing in memory and hard disk size, and, of course, looks.

Acorn also introduced a laptop computer called A4 that featured an ARM3 processor like the A5000, even though it had a slightly lower clock speed, and a black-and-white LCD screen. Curiously, it did not have a built-in pointing device, so users had to resort to a conventional Acorn three-button mouse.

The A7000, despite its name being reminiscent of the Archimedes naming conventions, was actually a low-end Risc PC – the line of RISC OS computers that succeeded the Archimedes in 1994.

Significance and impact

The Archimedes was one of the most powerful home computers available during the late 1980s; its main CPU was faster than the stock 68000s found in the more popular Atari ST and Commodore Amiga machines.

Despite a technical edge having been fully realised upon the release of RISC OS 2 in 1989, the Archimedes only ever met a moderate success, becoming very much a 'minority' platform outside of niche markets (not unlike the Apple Macintosh). The education markets of the UK, Ireland and Australasia were among the platform's most dominant zones of importance, along with specialised professional work such as radio, medical and train station management and music publishing. The success of the Archimedes in British schools was due partly to the Computers for Schools scheme organised by the Tesco supermarket chain in association with Acorn, and most students/pupils in the aforementioned countries in the early 90s will have seen/used an Archimedes.

The platform was very unusual in that it was and still is largely unknown outside of a handful of countries where most of its sales occurred. Very few people in Asia or the USA have ever heard of the Archimedes.

By the early 1990s however, the UK educational market which had been Acorn's perennial "cash cow" was beginning to turn away from the Archimedes. Many schools (particularly in Scotland for example) were now turning to the Macintosh. Meanwhile, the IBM Compatible PC was aligning itself as a contender with its increasing functionality as a multimedia computer, made possible by developments such as the Intel 486 processor and the Windows 3.0 operating system.

See also

• BBC Micro predecessor
• Risc PC The next generation Archimedes
• Acorn Computers Ltd

External links

• Acorn Archimedes site (http://acorn.revivalteam.de)
• arcem machine emulator released under the GNU GPL (http://arcem.sf.net/)
• Archie Archimedes emulator (link broken) (http://www.geocities.com/SiliconValley/Campus/5427/)
• RedSquirrel ARM machine emulator (http://www.red-squirrel.org)
• Virtual Acorn (http://www.virtualacorn.co.uk) - commercial Archimedes / RISC OS emulation package
• Acorn Archimedes memories (http://www.doyouremember.co.uk/memory.asp?memID=2232)
• Acorn Archimedes Emulator related site (http://www.diskimage.co.uk/)

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