General Architecture of Computer
Input Unit: Data and instructions must enter the computer system, before any computation can be performed on the supplied data. This task is performed by the input unit, which the external environment with the computer system. Data and instructions enter input units, which depend upon the particular device used. For example, data are entered from a keyboard in a manner similar to typing, and this differs from the way in which data are entered through a scanner, which is another type of input device. However, regardless of the form in which they receive their inputs, all input devices must transform the input data into binary codes, which the primary memory of a computer is designed to accept. This transformation is accomplished by units input interfaces. Input interfaces are designed to match the unique physical or electrical characteristics of input devices, to the requirements of the computer system.
In short, the following functions are performed by an input unit:
It accepts the instructions and data from the outside world.
It converts these instructions and data in computer acceptable form.
It supplies the converted instructions and data to the computer system for further processing.
Output Unit: The job of an output unit is the reverse of that of an input unit. It supplies the information obtained from data processing, to the outside world. Hence, it links the computer with the external environment. As computers work with binary code, the results produced are also in the binary form. Hence, before supplying the results to the outside world, they must be converted to the human acceptable form. This is accomplished by units called output interfaces. Output interfaces are designed to match the unique physical or electrical characteristics of the outside devices to the requirements of the external environment.
In short, the following functions are performed by an output unit:
It accepts the result produced by the computer, which are in coded form, and hence, cannot be easily understood by us.
It converts these coded results to human acceptable form.
It supplies the converted results to the outside world.
Storage Unit: The data and instructions, which are entered into input units, have to be stored inside the computer, before the actual processing starts. Similarly, the results produced by the computer after processing, must also be kept somewhere inside the computer system, before being passed on to the output units. Moreover, the intermediate results produced by the computer, must also be preserved for ongoing processing. The storage unit of a computer is designed to crater to all these needs. It provides space for sorting data and instructions, space for intermediate results, and space for the final results.
In short, the specific functions of the storage unit are to hold:
The data and instructions required for processing.
Intermediate results of processing.
Final results of processing, before these results are released to an output device.
Arithmetic Logic Unit: The arithmetic logic unit of a computer system 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 are made in the ALU. The data and instructions, stored in the primary storage before processing, are transferred as and when needed to the ALU, where processing takes place. No processing is done in the primary storage, until needed later. Hence, data may move from primary storage to ALU, and back again to storage, many times, before the processing is over the type and number of arithmetic and logical operations, which a computer can perform, is determined by the engineering design of ALU. However, almost all ALUs are designed 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 ALU know, what should be done with the data once they are received? Moreover, how is that only the final results are sent to the output device, and not the intermediate results? All this is possible due to the control unit if the computer 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 the main memory, interprets the instructions, and issues signals, which cause other units of the system to execute them.
Central Processing unit: The control and the arithmetic logic unit of a computer system are jointly known as the Central Processing Unit. The CPU in the brain of a computer system. In a human body, all major decisions are taken by the brain, and the other parts of the body function as directed by the brain. Similarly, in a computer system, all major calculations and comparisons are made inside CPU, and the CPU is responsible for activating and controlling the operations of other units of the computer system.
Input Unit: Data and instructions must enter the computer system, before any computation can be performed on the supplied data. This task is performed by the input unit, which the external environment with the computer system. Data and instructions enter input units, which depend upon the particular device used. For example, data are entered from a keyboard in a manner similar to typing, and this differs from the way in which data are entered through a scanner, which is another type of input device. However, regardless of the form in which they receive their inputs, all input devices must transform the input data into binary codes, which the primary memory of a computer is designed to accept. This transformation is accomplished by units input interfaces. Input interfaces are designed to match the unique physical or electrical characteristics of input devices, to the requirements of the computer system.
In short, the following functions are performed by an input unit:
It accepts the instructions and data from the outside world.
It converts these instructions and data in computer acceptable form.
It supplies the converted instructions and data to the computer system for further processing.
Output Unit: The job of an output unit is the reverse of that of an input unit. It supplies the information obtained from data processing, to the outside world. Hence, it links the computer with the external environment. As computers work with binary code, the results produced are also in the binary form. Hence, before supplying the results to the outside world, they must be converted to the human acceptable form. This is accomplished by units called output interfaces. Output interfaces are designed to match the unique physical or electrical characteristics of the outside devices to the requirements of the external environment.
In short, the following functions are performed by an output unit:
It accepts the result produced by the computer, which are in coded form, and hence, cannot be easily understood by us.
It converts these coded results to human acceptable form.
It supplies the converted results to the outside world.
Storage Unit: The data and instructions, which are entered into input units, have to be stored inside the computer, before the actual processing starts. Similarly, the results produced by the computer after processing, must also be kept somewhere inside the computer system, before being passed on to the output units. Moreover, the intermediate results produced by the computer, must also be preserved for ongoing processing. The storage unit of a computer is designed to crater to all these needs. It provides space for sorting data and instructions, space for intermediate results, and space for the final results.
In short, the specific functions of the storage unit are to hold:
The data and instructions required for processing.
Intermediate results of processing.
Final results of processing, before these results are released to an output device.
Arithmetic Logic Unit: The arithmetic logic unit of a computer system 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 are made in the ALU. The data and instructions, stored in the primary storage before processing, are transferred as and when needed to the ALU, where processing takes place. No processing is done in the primary storage, until needed later. Hence, data may move from primary storage to ALU, and back again to storage, many times, before the processing is over the type and number of arithmetic and logical operations, which a computer can perform, is determined by the engineering design of ALU. However, almost all ALUs are designed 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 ALU know, what should be done with the data once they are received? Moreover, how is that only the final results are sent to the output device, and not the intermediate results? All this is possible due to the control unit if the computer 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 the main memory, interprets the instructions, and issues signals, which cause other units of the system to execute them.
Central Processing unit: The control and the arithmetic logic unit of a computer system are jointly known as the Central Processing Unit. The CPU in the brain of a computer system. In a human body, all major decisions are taken by the brain, and the other parts of the body function as directed by the brain. Similarly, in a computer system, all major calculations and comparisons are made inside CPU, and the CPU is responsible for activating and controlling the operations of other units of the computer system.
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