upgraded to a powerful Motorola 68020 with a 68881 FPU, and a new version of the Macintosh operating system was also released which incorporated color capabilities and cooperative multitasking. The Mac II was quite expensive, costing $5498 in a standard configuration with 1 Mb of RAM and a 40 Mb hard disk. Nevertheless, the verdict was unanimous. This was the ultimate Mac - a colorful, multitasking, all-singing, all-dancing high performance machine. Unfortunately, most applications still treated the machine as if it were black and white, at least for a while.The Acorn ArchimedesThe Archimedes (lovingly called the Arc) was the first RISC based personal computer. Introduced in 1987, the Archimedes was based on Acorn's ARM architecture (ARM stood for Advanced RISC Machine). The ARM was a simple RISC architecture with 16 registers and no floating point support. The initial ARM implementations concentrated on low cost by using a short 3-stage pipeline. A unique feature of the ARM was that every instruction had a set of condition codes which indicated under what conditions it should be executed. This enabled simple conditional execution, which eliminated many branches and improved performance.For a home computer, the Archimedes packed quite a punch. The original Archimedes A305 only had 512 Kb of RAM and monochrome graphics, but its 4 MIPS ARM2 processor offered much better performance than a 68020 based Macintosh II or an 80386 based PC. Later models used the even faster ARM3 processor and added fast Amiga-like color graphics, more memory (up to 4 Mb), and a floating point co-processor. The Archimedes' RISC-OS operating system featured multitasking and a graphical user interface.The Archimedes sold quite well in the British educational market, which had been Acorn's primary market for its earlier 6502 based BBC machines. Unfortunately, the Archimedes was not a success in the wider marketplace, due mainly to the lower price and larger softwa...
