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Central processing unit is the brain of computer system. We use to control all input and output connections inside and outside of the computer to produce correct answer for their users it conrols and supervises all the units in a computer. It takes information from the input unit an dform the memory, and uses it according to the instruction already given to the computer from functional point of view CPU consist of three parts.
- Arithmetic and Logic Unit(ALU):
- Control Unit(CU)
- Memory Unit(MU)
Arithmetic and Logic Unit(ALU):
The ALU in any microprocessor which provides calculations including additions, subtraction, multiplication and division. It can also performs logical operations like comparing two numbers to logical operations like comparing two numbers to see which number is greater than, less than or equal to another number. The ALU performs million of calculations and comparision at a very high speed.
Control Unit(CU):
The Control unit acts like a traffic police man controlling the movements of vehicles on the road, the conrol unit directs and co-ordinates the entire computer system. Its function controlling the input/output units and the arithmetical/logical operation of the CPU, and transferring data to and front storage, within given design limits. The unit direct the system according to the procedures designed by its human operators and programmers.
Memory Units:
Memory units is the place where the computer program and data are stored during processing. It is the area through which all the data which is input or output of the CPU must pass. It is monitored by CU, which keeps tracks of every thing in the storage. It is a random access device, which consist of thousands upon thousands of storage location each of which can directly reached by CU. Each storage location is distinguish by the address. Memory unit consist of two parts namely.
- ROM (read only memory)
- RAM(random access memory)
ROM:
Rom is a part of memory unit it contains permanently stored information. When the power is switched off. ROM does not wash away or available to a computer to read and process but not to be changed is kept on ROM. This information is stored on small pieces of memory chips, before the computer isd assembled.
RAM:
This part of memory consists of blank chips and hence the computer can use it to store and retrieve (write and read) information during its processing. The information stored in RAM is volatile i.e, when the compter is shutdown or power failure the information or data stored is lost.
