The word “computer “comes from the word “compute “which means to calculate.
So a computer is normally considered to be a calculating device that performs arithmetic operations at enormous speed.
A computer is an electronic device which is used to perform operation on raw data as per instruction given by user. They are
1) It accepts data or instructions through input,
2) It stores data,
3) It can process required data by the user,
4) It gives results as production, and
5) It controls all functions inside the computer
Computer is an electronic device which performs tasks given by user with extremely fast speed and accuracy. Like any other device or machine, a computer system has also a number of parts. A computer system can be blocked into mainly three parts:
Input Unit
Central Processing Unit
Output Unit
1.Input unit
Input unit is a unit that accepts any input device. The input device is used to input data into the computer system.
Function of input unit:
It converts inputted data into binary codes. It sends data to main memory of computer
2. Central Processing Unit(CPU)
CPU is called the brain of a computer.
An electronic device that carries out the instruction given by a computer program.
A. Control unit (CU)-
The control unit manages the various components of the computer.
It reads instructions from memory and interpretation and changes in a series of signals to activate other parts of the computer.
It controls and co-ordinate is input output memory and all other units.
B. Arithmetic & Logic unit (ALU) –
The arithmetic logic unit (ALU), which performs simple arithmetic operation such as +,-, *, / and logical operation such as >, <, =<, <= etc.
C. Memory Unit (MU)-
Memory is used to store data and instructions before and after processing. Memory is also called Primary memory or internal memory. It is used to store data temporary or permanently.
Functions of CPU:
It controls all the parts and software and data flow of computer.
It performs all operations.
It accepts data from input device.
It sends information to output device.
Executing programs stored in memory
It stores data either temporarily or permanent basis.
It performs arithmetical and logical operations.
3. Output Unit
Output unit is a unit that constituents a number of output device. An output device is used to show the result of processing.
Function of Output unit:
it accepts data or information sends from main memory of computer
It converts binary coded information into HLL or inputted languages.
Computer System
All of the components of a computer system can be summarized with the simple equations.
COMPUTER SYSTEM = HARDWARE + SOFTWARE+ USER
- Hardware = Internal Devices + Peripheral Devices
All physical parts of the computer (or everything that we can touch) are known as Hardware.
- Software = Programs
Software gives “intelligence” to the computer.
- USER = Person, who operates computer.
Generation of computer:
First Generation (1940-56):
The first generation computers used vaccum tubes & machine language was used for giving the instructions. These computer were large in size & their programming was difficult task. The electricity consumption was very high. Some computers of this generation are ENIAC, EDVAC, EDSAC & UNIVAC-1.
Second Generation(1956-63):
In 2nd generation computers, vaccum tubes were replaced by transistors. They required only 1/10 of power required by tubes. This generation computers generated less heat & were reliable. The first operating system developed in this generation.
The Third Generation(1964-71):
The 3rd generation computers replaced transistors with Integrated circuit known as chip. From Small scale integrated circuits which had 10 transistors per chip, technology developed to MSI circuits with 100 transistors per chip. These computers were smaller, faster & more reliable. High level languages invented in this generation.
The fourth Generation(1972- present):
LSI & VLSI were used in this generation. As a result microprocessors came into existence. The computers using this technology known to be Micro Computers. High capacity hard disk were invented. There is great development in data communication.
The Fifth Generation (Present & Beyond):
Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today. The use of parallel processing and superconductors is helping to make artificial intelligence a reality. Quantum computation and molecular and nanotechnology will radically change the face of computers in years to come.
