At one time computers were huge bulky machines which weighed many tons, and operated using old time "vacuum tubes." The invention of the silicon transistor in the early 1940's revolutionized the electronics industry. During the 1970s U.S. companies pioneered new manufacturing techniques called Very Large Scale Integration [VLSI]. It permitted the production of very compact electronic devices. Instead of one transistor, many (in fact, millions on a modern microprocessor) were integrated into a single silicon wafers that could be cheaply mass produced. Commonly referred to as microchips. they led to the development of the microprocessor, a CPU contained on a single microchip sometimes simply called a "computer chip". Pictured below is a highly enlarged photograph (with false coloring) of a Pentium chip manufactured by Intel.
The microprocessor plugs into a socket which connects it to the motherboard's external bus. A
The instruction codes are fed into the control unit which then activates the circuits that move the data into the Arithmetic/Logic Unit's [ALU] registers and carry out the requested operations. In order to speed up arithmetic operations, a math coprocessor is used. At one time the math coprocessor was an additional chip which was purchased separately. Today's microprocessors have the math coprocessor built-in to the microprocessor as a standard feature. As the microprocessor fetches the instruction codes and data from main memory it queues them up in its internal [L1] cache memory so they will be ready when needed, speeding up the operations. (More about cache memory is explained in the next topic reading on memory.)
· CPU Guide: http://www.sysdoc.pair.com/cpu.html
The CPU's operations are synchronized by the CPU's clock The clock of a microprocessor is a quartz crystal that is the same as the one you probably
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