Microprocessor
EVOLUTION OF MICROPROCESSORS
INTRODUCTION
A microprocessor incorporates the functions of a computer's central processing unit (CPU) on a single integrated circuit (IC),or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and provides results as output. It is an example of sequential digital logic, as it has internal memory. Microprocessors operate on numbers and symbols represented in the binary numeral system. The advent of low-cost computers on integrated circuits has transformed modern society. General-purpose microprocessors in personal computers are used for computation, text editing, multimedia display, and communication over the Internet. Many more microprocessors are part of embedded systems, providing digital control of a myriad of objects from appliances to automobiles to cellular phones and industrial process control.
EVOLUTION During the 1960s, computer processors were constructed out of small and medium-scale ICs each containing from tens to a few hundred transistors. For each computer built, all of these had to be placed and soldered onto printed circuit boards, and often multiple boards would have to be interconnected in a chassis. The large number of discrete logic gatesused more electrical power—and therefore, produced more heat—than a more integrated design with fewer ICs. The distance that signals had to travel between ICs on the boards limited the speed at which a computer could operate. Microprocessors integrated into one or a few large-scale ICs the architectures that had previously been implemented using many medium- and small-scale integrated circuits. Continued increases in microprocessor capacity have rendered other forms of computers almost completely obsolete (see history of computing hardware), with one or more microprocessors used in everything from the smallest
INTRODUCTION
A microprocessor incorporates the functions of a computer's central processing unit (CPU) on a single integrated circuit (IC),or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and provides results as output. It is an example of sequential digital logic, as it has internal memory. Microprocessors operate on numbers and symbols represented in the binary numeral system. The advent of low-cost computers on integrated circuits has transformed modern society. General-purpose microprocessors in personal computers are used for computation, text editing, multimedia display, and communication over the Internet. Many more microprocessors are part of embedded systems, providing digital control of a myriad of objects from appliances to automobiles to cellular phones and industrial process control.
EVOLUTION During the 1960s, computer processors were constructed out of small and medium-scale ICs each containing from tens to a few hundred transistors. For each computer built, all of these had to be placed and soldered onto printed circuit boards, and often multiple boards would have to be interconnected in a chassis. The large number of discrete logic gatesused more electrical power—and therefore, produced more heat—than a more integrated design with fewer ICs. The distance that signals had to travel between ICs on the boards limited the speed at which a computer could operate. Microprocessors integrated into one or a few large-scale ICs the architectures that had previously been implemented using many medium- and small-scale integrated circuits. Continued increases in microprocessor capacity have rendered other forms of computers almost completely obsolete (see history of computing hardware), with one or more microprocessors used in everything from the smallest