Evolution of Microprocessor

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Evolution of Microprocessor
It is interesting to note that the microprocessor had existed for only 10 years prior to the creation of the PC! Intel invented the microprocessor in 1971; the PC was created by IBM in 1981. Now more than 20 years later, we are still using systems based more or less on the design of that first PC. The processors powering our PCs today are still backward compatible in many ways with the 8088 that IBM selected for the first PC in 1981. November 15, 2001 marked the 30th anniversary of the microprocessor, and in those 30 years processor speed has increased more than 18,500 times (from 0.108MHz to 2GHz).The 4004 was introduced on November 15, 1971 and originally ran at a clock speed of 108KHz (108,000 cycles per second, or just over one-tenth a megahertz). The 4004 contained 2,300 transistors and was built on a 10-micron process. This means that each line, trace, or transistor could be spaced about 10 microns (millionths of a meter) apart. Data was transferred 4 bits at a time, and the maximum addressable memory was only 640 bytes. The 4004 was designed for use in a calculator but proved to be useful for many other functions because of its inherent programmability. For example, the 4004 was used in traffic light controllers, blood analyzers, and even in the NASA Pioneer 10 deep space probe! In April 1972, Intel released the 8008 processor, which originally ran at a clock speed of 200KHz (0.2MHz). The 8008 processor contained 3,500 transistors and was built on the same 10-micron process as the previous processor. The big change in the 8008 was that it had an 8-bit data bus, which meant it could move data 8 bits at a timetwice as much as the previous chip. It could also address more memory, up to 16KB. This chip was primarily used in dumb terminals and general-purpose calculators. The next chip in the lineup was the 8080, introduced in April 1974, running at a clock rate of 2MHz. Due mostly to the faster clock rate, the 8080 processor had 10...
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