Acorn - 300/400 Series  Archimedes A420
aco_a420

The Acorn Archimedes A420

The Acorn Archimeds A420 was similar to the A410 model, but with 2MByte of memory and the same ARM2 RISC CPU running at 8MHz and upgraded backplane over the 300 series.

Acorn Archimedes Computers

The Acorn Archimedes computer was the commercially available computer to use the RISC (Reduced Instruction Set CPU) architecture. The first models were launched in 1987, and Acorn developed updated models of the machines until the early 1990's. The CPU in the Acorn machines is the ARM chip, which stands for Acorn RISC Machine. ARM Chips are still used today, one popular example is the iPhone.

Arthur Operating System

The Acorn Archimedes computers were initially shipped with the Arthur OS, but could be upgraded to RISC OS, by replacing the ROM chips that contained the operating system. Because of these ROMs, the computer would boot immediatly into it's GUI, similar to the Atari ST line of computers. This gave them a significant advantage over PC's that loaded the operating system from disk.

The early Archimedes computers used the Arthur operating system, which was replaced in 1989 with RISC OS. RISC-OS featured co-operative multitasking, task management, solid window manipulation, adaptive rendering of bitmaps and coloring, and above all stability that the Arthur OS lacked. New applications quickly started to take advantage of the RISC-OS resulting in mature software such as Acorn Desktop Publisher, and even a PC Emulator.

By Acorn CPU ARM2 @8MHz Memory 2MB RAM Sound 8 channel, 8 bit stereo sound Sprites 1 hardware sprite Display 640x256, 256 colors, 640x512, 16 colors, 1024x1024, mono Display Chip VIDC1A Video Display Processor Sound Chip Integrated CPU Class ARM Developed by BBC
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Acorn BBC / Archimedes
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Archimedes  A420
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