Intel 80386 And The Attack of The Clone PCs

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Intel 80386 And The Attack Of The Clone PCs - Acorn Archimedes

In 1985 Intel introduced its new CPU, the 32-bit 80386 or i386. The i386 was significantly faster than its predecessor, the 80286, and fully compatible with all existing applications, even the ones that were developed for the 8086 and 8088 processors. The i386's speed ranged from 12 MHz to 40 MHz. An i386 clocked at 33 MHz was able to perform 11.4 million instructions per second (MIPs) while a 80286 CPU clocked at 12 MHz could only perform 1.8 MIPs. As you can see, the difference is huge and this is why the i386 is a landmark in Intel's history.

To the great surprise of the computing community, the first PC equipped with an i386 didn't come from IBM, which was a leader in the PC market. Instead, the PC with the i386 chip was introduced by Compaq, which later merged with Hewlett-Packard. We should mention that Intel initially approached IBM, offering its new CPU, but the company refused; IBM wanted to keep using the older 80286 because it had manufacturing rights for the CPU. Ultimately, the Compaq i386 was a great success and made the PC clones (i.e. computers compatible with IBM PCs) highly popular.

In the mid-1980s an English computer manufacturer, Acorn Computers, decided to find a replacement for the aged 8-bit 6502 CPU that it used until that time. Acorn approached Intel in an effort to get the required rights to use the 80286 CPU, but the respponse was negative. This forced Acorn to build its own processor, and the final result was ARM (Acorn Risc Machine), which was a powerful RISC (Reduced Instruction Set Computing) type processor. RISC CPUs achieved higher performance than the CISC (Complex Instruction Set Computing) CPUs through the use of a smaller set of simple, but frequently-used commands.