Computer technology has made incredible progress in the roughly 55 years since
the first general-purpose electronic computer was created. Today, less than a
thousand dollars will purchase a personal computer that has more performance,
more main memory, and more disk storage than a computer bought in 1980 for
$1 million. This rapid rate of improvement has come both from advances in the
technology used to build computers and from innovation in computer design.
Although technological improvements have been fairly steady, progress arising
from better computer architectures has been much less consistent. During the
first 25 years of electronic computers, both forces made a major contribution; but
beginning in about 1970, computer designers became largely dependent upon integrated
circuit technology. During the 1970s, performance continued to improve
at about 25% to 30% per year for the mainframes and minicomputers that dominated
the industry.
The late 1970s saw the emergence of the microprocessor. The ability of the
microprocessor to ride the improvements in integrated circuit technology more
closely than the less integrated mainframes and minicomputers led to a higher
rate of improvement—roughly 35% growth per year in performance.