The next revolution - The A5000 (1991).

By mid 1991 the Archimedes range had been on sale for almost four years, in various different versions, and it was time for the next development in the Acorn ARM-based computers to be released. This machine, launched in September 1991, was called the A5000.

The A5000 was fitted with an ARM3 processor, but with a slower clock speed than the one in the A540 (25 MHz against 33 MHz). There were two models available, one with 1 Mb of RAM and no hard disc and one with 2 Mb of RAM and a 40 Mb IDE hard disc. Both machines were capable of being upgraded to 4 Mb. Like the A540, the memory was clocked at 12 MHz. The A5000 motherboard was redesigned, but was not modular like the A540 motherboard. The range of interfaces available was similar to the existing A4xx/1 range, with the main difference being that the monitor connector was a PC standard 15-pin VGA connector, rather than a 9-pin D-type connector. The A5000 was also the first 32 bit Acorn machine to feature a bi-directional parallel port and have a PC-style serial port (the A3xx, A4xx, A3000 and A4xx/1 serial ports had slightly different wiring to the standard PC port).

There were four main changes between the A5000 and earlier machines. The first was the redesigned case. This was in a style similar to the PCs of the day, a rectangular grey three box system. The internal design was totally different to the previous A4xx/1 machines, with provision for a second internal hard drive (or 3.5" floppy drive). The power supply was on the right side of the case, rather than the left side, and contained an integral fan. The second change was support for DOS 1.44 Mb floppy discs, and a new Acorn-only 1.6 Mb disc format, "F", to complement the existing "E" 800 Kb format. The third was the decision to dump the old ST506 hard drives and start including IDE drives. The fourth, and most significant, change was with the operating system - the A5000 was supplied with RISC OS 3.

While RISC OS 3 maintained the look and feel of RISC OS 2, it was a much more advanced system. The ROMs that the operating system were contained in were four times the size of the RISC OS 2 ROMs, 2 Mb compared to 512 Kb. The biggest improvement was the new multitasking operation of the filer - with RISC OS 2, if you were formatting a disc you couldn't do anything else until the format was finished, but with RISC OS 3 the system could still multitask. A number of the main RISC OS applications (including Draw, Edit and Paint) were moved in to ROM, along with the three most commonly used font families and other resources. The remaining applications were updated. Other updates included an increase in the maximum number of concurrent tasks, the ability to read and write DOS discs (and read other disc formats) without having to load any extra modules, the addition of a screen blanker and improved printer support.

The A5000 fitted in to the Acorn range below the A540 but above the A440/1 (effectively superseding it). The 1 Mb version cost £999 excluding VAT and the 2 Mb version cost £1499 excluding VAT.

At the same time the A5000 was announced, the Learning Curve package, previously only available with the A420/1, was updated. Two new versions were available, one featuring the A3000 and the other featuring the A5000. Both included First Word Plus, Genesis Plus and a selection of games, and the A5000 version also included Acorn DTP and the latest version of the PC Emulator package. The A3000 LC cost £999 excluding VAT (but including a colour monitor) and the A5000 LC cost £1799 excluding VAT (but including a multiscan monitor).

One other thing that happened in 1991 was that the ARM chip making concern was spun off to form an independant subsidury, Advanced RISC Machines, or ARM, Ltd. Acorn and Apple both held a 43% share, with VLSI Technology Ltd holding the remainder.

After the A5000 was released, Acorn once again turned their attention to a slightly different market. This time, it was the market for portable computers. The Acorn solution was released in 1992, and was called the A4.

Next: Entry into the portable world - The A4 (1992).

Click here to return home or here to return to the Technical History of Acorn.

Robert McMordie

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