The history of the IBM PC, part two: the DOS empire strikes
Since I abused the first part in Ars' two-parter on the history of the IBM PC for my own selfish purposes, it's only fair to use the publication of part two to actually talk about the subject matter at hand.
In November 1979, Microsoft's frequent partner Seattle Computer Products released a standalone Intel 8086 motherboard for hardcore hobbyists and computer manufacturers looking to experiment with this new and very powerful CPU. The 8086 was closely related to the 8088 that IBM chose for the PC; the latter was a cost-reduced version of the former, an 8-bit/16-bit hybrid chip rather than a pure 16-bit like the 8086.
IBM opted for the less powerful 8088 partly to control costs, but also to allow the use of certain hardware that required the 8-bit external data bus found on the 8088. But perhaps the biggest consideration stemmed, as happens so often, from the marketing department rather than engineering. The 8086 was such a powerful chip that an IBM PC so equipped might convince some customers to choose it in lieu of IBM's own larger systems; IBM wanted to take business from other PC manufacturers, not from their own other divisions.
The IBM PC and its compatibles changed the computing landscape more than any other platform, and to this day it remains the archetype of what people think of when they think of "computer". While the archetypal computer is surely changing into a laptop or even a smartphone, they've got a long way to go before they push the PC out of the collective consciousness as the "default" computer.