To be more precise calculations are performed and all

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Unformatted text preview: ystem is the place where the actual execution of the instructions takes place during the processing operation. To be more precise, calculations are performed and all comparisons (decisions) are made in the ALU. The data and instructions, stored in the primary storage prior to processing, are transferred as and when needed to the ALU where processing takes place. No processing is done in the primary storage unit. Intermediate results generated in the ALU are temporarily transferred back to the primary storage until needed at a later time. Data may thus move from primary storage to ALU and back again to storage many times before the processing is over. After the completion of processing, the final results, which are stored in the storage unit, are released to an output device. The type and number of arithmetic and logic operations that a computer can perform is determined by the engineering design of the ALU. However, almost all ALUs are designed to perform the four basic arithmetic operations (add, subtract, multiply, and divide), and logic operations or comparisons such as less than, equal to, and greater than. CONTROL UNIT How does the input device know that it is time for it to feed data into the storage unit? How does the ALU know what should be done with the data once they are received? And how is it that only the final results are sent to the output device and not the intermediate results? All this is possible because of the control unit of the computer system. By selecting, interpreting, and seeing to the execution of the program instructions, the control unit is able to maintain order and direct the operation of the entire system. Although, it does not perform any actual processing on the data, the control unit acts as a central nervous system for the other components of the computer system. It manages and coordinates the entire computer system. It obtains instructions from the program stored in main memory, interprets the instructions, and issues signals that cause other units of the system to execute them. CENTRAL PROCESSING UNIT The control un...
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This document was uploaded on 04/07/2014.

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