Are an electronic device that stores, retrieves, and processes
data.
Consist of hardware and software.
Computer Applications
Have made our life much easier.
Include Airline and railway reservations, telephone and
electricity bills, banking, medical diagnoses, weather forecasts.
Generation of Computer
Following are the five generations of computer:
First Generation — 1940-1956: Vacuum Tubes
Second Generation —1956-1963: Transistors
Third Generation — 1964-1971: Integrated Circuits
Fourth Generation — 1971-Present: Microprocessors
Fifth Generation — Present and Beyond: Artificial Intelligence
First Generation Computers
The first generation computers used valves leading to huge size
& cost. The UNIVAC and ENIAC computers are example of first
generation computing devices.
The UNIVAC was the first commercial computer delivered to a
business client, the U.S. Census Bureau in 1951.
Second Generation Computers
The second generation computer used transistors. In a span of
ten years, transistors that were more efficient and cheaper
replaced valves.
Third Generation Computers
The third generation computers used integrated circuits(IC). In the early sixties, a major break though was achieved when hundreds of transistors could be placed on a single silicon chip. This IC became the basis of the third generation.
Fourth Generation Computers
The fourth generation computes used microprocessors(CPU). With the introduction of very large scale integration (VLSI), thousands of transistors could be placed on a single chip.
In 1981 IBM Introduced its first computer for the home user and in 1984 Apple introduced the Macintosh. Fourth generation computers also saw the development of Graphical User Interface (GUIs). The mouse and handheld devices.
Fifth Generation Computers
Try to infuse intelligence into computers.
Are still in its infancy.
Computer System
Personal Computer or Microcomputers
Is small in size but capable of handling large tasks.
Minicomputer
Is a small, general-purpose computer.
Mainframe Computers
Are used in large organizations for large-scale jobs.
Supercomputers
Are the largest, fastest and the most expensive computers in the world.
Are used for Bio-medical research, weather forecasting, chemical analysis in laboratory, complex scientific, and defense applications.
Benefits and Limitations of Computers
A computer provides three basic benefits
Speed
Accuracy
Diligence
Components of a PC System
The components of a PC System includes
System Unit (CPU)
Visual Display Unit (VDU)
Microphone
Keyboard
Mouse
Printer
Components of a PC System
Following figure shows the components of a PC System.
How Does a Computer Work?
Working of a Computer
Input-Process-Output (I-P-O).
Hardware Of Computer
Input – Output Devices
Keyboard
Is an input device and provides different keys to perform various operations.
Mouse
Is an input device, whose movement causes the corresponding movement of a pointer on the screen.
VDU
Is an output device that is similar to a TV screen and can display both text and graphic images.
Printer
Is an output device that is used to obtain output on paper.
Microphone
Is an input device that allows a user to speak to the computer to enter data and instructions into the computer or it is used to record sound.
Joystick
Is a pointing device, used for computer games and ultrasound scanners in hospitals.
Scanner
Is an input device, used to capture information, such as, photographs and documents on paper and translate the information into a raster (bitmap) computer image.
Speaker
Are used on a multimedia machine to listen to the sound files.
Processing Devices
System Unit
Is used for the processing of data.
Includes a component called microprocessor, which is involved in the actual processing.
Motherboard
Is one of the components of the system unit.
Has standard circuitry that is needed for the PC, as well as extra set of expansion slots.
CPU
Is the brain of the computer and is placed inside the system unit.
Storage Devices
Primary Storage Device
For a computer is Random Access memory (RAM).
Secondary Storage Device
Hard Disk
Is a high storage capacity disk and is permanently placed inside the computer.
Floppy Disk
Is a portable secondary storage device with which you can copy the data from one machine to another.
Compact Disk
Is also a portable secondary storage device to store data.
Software
Is a set of program written to achieve a common objective.
Can be categorized into two types:
Application Software
Are the software specially suited for specific applications.
For example, software for billing systems, accounting software or software that enables the creation and storage of documents.
System Software
Is very important for the working of the PC.
For example, operating system performs the task of storage management and device management.
Internet
Is a very large network that connects computers all over the world.
Is a huge encyclopedia of information.
To access the Internet, you need a modem and a Web browser.
Modem
Is used to connect your computer to any other computer in the world via telephone lines.
Converts data on the computer into a form that can be transferred over telephone lines.
Web Browser
Is a software application that provides a graphical view of the Internet.
Gives you access to Web sites, which consists of Web pages.