An operation, in mathematics and computer science, is an action that is performed to complete a given task. There are five basic types of computer operations: input, processing, output, storage, and control.
A digital computer can be divided into the following basic units;
Input Unit
CPU - Central Processing Unit
ALU - Arithmetic Logic Unit
CU - Control Unit
Memory Unit
Output Unit
01. Input Unit
Input devices read the required data into the machine. A computer cannot function unless it is translated into a language it understands. An input unit is provided to translate all the data into an electronic pulse so that the computer can understand it.
Most of what constitutes a program must be fed into the machine along with all the data to be used in computations. Some of the more common input devices are keyboards, punch-cards, magnetic tape readers, etc.
02. Central Processing Unit
CPU is the Central Processing Unit which is a major part of the computer. All computer processing is done in this. It also controls the activities of the entire computer configuration. It consists of three main components, namely;
ALU - Arithmetic Logic Unit
CU - Control Unit
Memory Unit
Functions of a CPU
1. Store the instructions as well as the data.
2. Control the order of operations according to the stored instructions.
3. Issue commands to all parts of the computer system.
4. Perform data processing and send results to output.
i. Arithmetic Logic Unit
The ALU executes or operates on the data available in the main memory and after processing sends them to the memory once again.
Functions of Arithmetic Logic Unit
1. It performs arithmetic operations like addition, subtraction, multiplication and division.
2. Performs some logical actions on the basis of AND and OR functions.
The ALU consists of several Accumulators & Registers. It receives all the data from the main memory as directed by the Control Unit (CU) based on the program given to it. The data gets loaded into the accumulator in the ALU. Certain logical operations of the ALU enable the computer to make quality decisions.
ii. Control Unit
The control unit or control unit directs all the functions inside the computer. It is known as the heart of the computer because it controls and coordinates all the hardware operations of the CPU and input-output devices.
The Main Functions Of The Control Unit
1. It gives commands to transfer the data from the input device to the arithmetic logic unit (ALU) in memory.
2. It also transfers the results from memory to the output device for printing.
3. It stores the program in memory, takes instructions one by one, interprets them and communicates comments to other units or issues appropriate commands.
iii. Memory Unit
It is also called the main or primary memory of the computer, as it is capable of storing information, which can be recalled or accessed when required. Program instructions must be stored in main memory so that it can operate automatically.
Memory is made up of electronic components, due to which its operation is extremely fast. Since the main high speed memory is limited in size, the rest of the programs and data are kept in secondary storage devices also called backing storage devices ( BSD ).
The Main Functions Of A Memory
1. Instructions, which are ready for execution by other components of the CPU.
2. Instructions, which are to be followed at present.
3. Data ready for processing.
4. Recently processed data.
5. Processed data ready for output.
03. Output Unit
Output The results of any computer processing to be reported to the user. Output devices translate computer output into a form understood by humans. Most of the output devices are directed by the control unit ( CU ), which also carries the necessary information to be supplied to them. Common output devices are CRT displays, printers, card-readers, etc.
Basic Units Of A Computer
The five basic units of a computer can be summarized as shown in the table below;
Unit | Functions |
Input Unit | Reads Information From Input Device And Feeds To The Computer In Coded Form. |
Storage Unit | Stores Program Instructions And Data. |
Arithmetic & Logic Unit | Performs Arithmetic And Logic Operations. |
Control Unit | Interprets Program Instructions And Initiates Control Operations. |
Output Unit | Decode Information And Presents It To The User. |
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