computer

1. Advantages of using computers
There are severaladvantages and benefits of using computers.someof them are
discussed below
Speed
Speed is the most important characteristic of a computer.the computer can
performbillions of calculations in a fraction of a second .
For exampleif a student is asked to calculate the following product
The student will take few minutes to solveit, but a computer can solve millions of
Such problems in less then second.
Accurarcy
Computer is almost 100% accurate and it never makes mistakes.
Diligence
Besides being fast, a computer can do things over and over agai. Itnever gets
tired are bored. If wehave to write letter 100 times we will get tired. A cputer can
write letter even a million times but never gets tried are bored
Generation of computer
1
First Generation
The periodof first generation:1946-1954. Vacuumtube based.
Advantages
 Vacuumtubes were the only electronic component available during
those days.
 Vacuumtube technology made possibleto make electronic digital
computers.
 These computers could calculate data in millisecond

2. Disadvantages
 The computers were very large in size.
 They consumed a large amount of energy.
 They heated very soon due to thousands of vacuumtubes.
 They were not very reliable.
 Air conditioning was required.
 Constantmaintenance was required.
 Non-portable.
 Costly commercial production.
 Limited commercial use.
 Very slow speed.
 Limited programming capabilities.
 Used machine language only.
 Used magnetic drums which providevery less data storage.
 Used punch cards for input.
 Not versatile and very faulty

2
Second Generation
The period of second generation: 1954-1963. Transistor based.
Advantages
 Smaller in size as compared to the first generation computers.
 The 2nd generation Computers weremore reliable
 Used less energy and were not heated.
 Wider commercial use
 Better portability as compared to the firstgeneration computers.

3.  Better speed and could calculate data in microseconds
 Used faster peripherals like tape drives, magnetic disks, printer etc.
 Used Assembly languageinstead of Machine language.
 Accuracy improved.
Disadvantages
 Cooling systemwas required
 Constantmaintenance was required
 Commercial production was difficult
 Only used for specific purposes
 Costly and not versatile
 Puch cards were used for input
3
Third Generation
The periodof thirdgeneration:1965-1971. IntegratedCircuit based.
Advantages
 Smaller in size as compared to the first generation computers.
 The 2nd generation Computers weremore reliable
 Used less energy and were not heated.
 Wider commercial use
 Better portability as compared to the firstgeneration computers.
 Better speed and could calculate data in microseconds
 Used faster peripherals like tape drives, magnetic disks, printer etc.
 Used Assembly languageinstead of Machine language.
 Accuracy improved.
Disadvantages
 Cooling systemwas required

4.  Constantmaintenance was required
 Commercial production was difficult
 Only used for specific purposes
 Costly and not versatile
 Puch cards were used for input.
4
Fourth Generation
The period of fourthgeneration:1975-present. VLSI microprocessor
based.
Advantages
 Smaller in size as compared to previous generations.
 More reliable.
 Used less energy
 Produced less heat as compared to the previous two generations of
computers.
 Better speed and could calculate data in nanoseconds.
 Used fan for heat dischargeto prevent damage.
 Maintenance costwas low becausehardwarefailure is reare.
 Totally general purpose
 Could be used for high-level languages.
 Good storage
 Versatile to an extent
 Less expensive
 Better accuracy
 Commercial production increased.
 Used mouseand keyboard for input.

5. Disadvantages
 Air conditioning was required.
 Highly sophisticated technology required for the manufacturing of IC
chips.
5
Fifth Generation
The periodof fifthgeneration:1980-onwards. ULSI microprocessor
based
Advantages
 More powerfuland reliable than previous generations.
 Small in size
 Fastprocessing power with less power consumption
 Fan for heat discharging and thus to keep cold.
 No air conditioning required.
 Totally general purpose
 Commercial production
 Less need of repair.
 Cheapest among all generations
 All types of High level languages can be used in this type of
computers
Disadvantages
 The latest technology is required for manufacturing of
Microprocessors
Computer component

6. InputUnit
This unit contains devices with the help of which we enter data into computer.
This unit makes link between user and computer. The input devices translate the
information into the form understandable by computer.
CPU(CentralProcessingUnit)
CPU is considered as the brain of the computer. CPU performs all types of data
processing operations. It stores data, intermediate results and
instructions(program). It controls the operation of all parts of computer.
CPU itself has following three components
 ALU(Arithmetic Logic Unit)
 Memory Unit
 Control Unit
OutputUnit
Output unit consists of devices with the help of which we get the information
from computer. This unit is a link between computer and users. Output devices
translate the computer's output into the form understandable by users.
How Do Computers Work?
Computer Basics
To accomplish a task using a computer, you need a combination of hardware,
software, and input.
Hardware
consists of devices, like the computer itself, the monitor,
keyboard, printer, mouseand speakers. Insideyour computer there are morebits
of hardware, including the motherboard, whereyou would find the main
processing chips that make up the
central processing unit (CPU). Thehardwareprocesses thecommands it receives
fromthe software, and performs tasks of calculations.
Software

7. is the name given to the programs thatyou install on the computer to perform
certain types of activities. There is operating systemsoftware, such as the Apple
OS for a Macintosh, or Windows 95 or Windows 98 for a PC. There is also
application software, like the games we play or the tools we useto compose
letters or do math problems.
input
You providethe input. When you type a command or click on an icon, you are
telling the computer what to do. That is called input
Input, output and storage unit
• Input devices
• Identify input devices
• List input devices
• Functions of Input devices
• Output devices
• Identify Output devices
• List Output devices
• Functions of Output devices
• Storage devices
• Identify storage devices
• List storage devices
• Functions of storage devices