Acorn Archimedes A4000

Acorn Archimedes, the British rival of Amiga and Atari ST. People discussed a lot about it, but in Italy just a few actually had it. Finally it is mine! 🙂

It was the year 1987 and Britain's Acorn, in the wake of the good success of the BBC Master – and even before the BBC Electon – decided to participate in the technology race of the time, opposed to competitors that proposed mainly 16 bit, or hybrid ones at 16-32.
The very first model of this popular family of personal computers was called Archimedes 305, and was equipped with an ARM CPU clocked at 8MHz, fully at 32 bit (competitors was using the Motorola 680xx family of CPUs. Processors were substantially at 16 bit, with some registers using 32 bit), and with a range of video resolutions unprecedented for its time, i.e. a powerful 896×352 at 256 colors!
If the graphics was nothing short of thrilling, the audio section was even exaggerated: such as 8 independent voices, spread over two stereo channels.

The basic model was proposed with 512KB of RAM, expandable to 64MB. The mass storage consisted in a disk drive of 3.5″, able to store up to 800KB of data on each media, and a commonly installed hard disk, sized 20MB (basic model) up to 53MB.
The operating system was a little gem. Initially called ARTHUR, later became the famous RISC OS, still mourned by many users. Peculiarities of the operating system: was installed in ROM, and all updates involved a replacement of the chip in question, as it was for the Amiga.

At the dawn of the '90s, Archimedes family already had many members, increasingly sophisticated and powerful.
Towards the end of 1992, Acorn also expanded its range by introducing the A4000 model, that I'm lucky to own.
It was a slightly “streamlined” version of the serie's top, the A5000.

Acorn Archimedes A4000

CPU Case, keyboard and 3-buttons mouse

The A4000 model was equipped with an ARM 250 RISC CPU @ 12MHz, at 32 bit; Was counting on a RAM from 2 to 4MB, depending on grade, a 210MB hard disk, in addition to the floppy disk drive 3.5″ with 800KB capacity.
The graphics was reduced compared to the debut model, in order to contain costs, and make the Archimedes truly competitive in a market segment that became very fierce. One of the most interesting graphics mode, was without doubt the one at 640×512 with a palette of 4096 colors (simultaneous), with a VGA output (multisync).

The machine in my possession was purchased on ebay, at a price attractive enough. If it were not for shipping fees!! 🙂



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