10 INPUT DEVICES AND THEIR FUNCTIONS

1. KEYBOARD

A keyboard consists of a series of keys that can be pressed

to input commands or letters. These are used to write

documents but can be used to navigate user interfaces in

lieu of a mouse.

2. MOUSE

A mouse consists of a ball or laser that tracks the movement

of the device. The computer is able to register the

movement of the mouse and translate it as movement of the

cursor on the screen. A mouse also contain buttons that

allow the user to select objects, move windows or open

applications. Many also include a scrolling wheel to allow for

scrolling through long documents or Web pages.

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3. TRACKBALL

These devices work like a standard mouse except the users

rolls a ball inside a base rather than moving the device

across the table top. Many users prefer a trackball to a

mouse, because it involves less wrist movement, reducing

repetitive-motion issues.

4. TOUCHPAD

This is a device typically found on laptop computers. It works

like a mouse or trackball, except it's a flat panel you move

your finger across. The motion of your finger registers as

cursor movement on the screen. Many touchpads now

enable gestures to scroll through documents or zoom in on a

photo. Buttons are typically below the touchpad.

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5. GRAPHICS TABLET

These devices are used like a piece of paper and a pencil.

These allow artists to draw more naturally in a graphics

application. They have a stylus that looks like a plastic pencil

that you can use to draw on a flat panel. The device will

register the pressure of the user's hand to draw lighter or

darker lines on screen. Many even have erasers on the back

that allow you to erase mistakes with the stylus.

6. TOUCHSCREEN MONITOR

These devices double as an output and input device. They

display the computer environment on screen, and allow a

user to manipulate and interface with it just by touching the

screen. These can take the place of a mouse and even a

keyboard if a virtual keyboard application is installed.

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7. JOYSTICK

These devices are primarily used for computer gaming. They

consist of a stick on a base with various buttons that all have

different functions. It operates similar to a yoke on an

aircraft, making them suitable for flight simulators.

8. SCANNER

These devices allow a user to input a photograph or

document into the computer. By placing a piece of media in

a scanner, you can create an image file that can be opened

and manipulated on the computer.

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9. MICROPHONE

This is a device used to input voice data and sound. You hold

the microphone up to a source, most likely a person's mouth,

and it registers the sounds and inputs them into audio

recording applications. This will let you do many things, from

recording a song to talking to someone on Skype.

10. WEBCAM

This is a small video camera that takes video and inputs it

into the computer. These allow you to record and send small

videos or have a video chat with someone over the Internet.

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10 OUTPUT DEVICES AND THEIR FUNCTIONS

1. COMPUTER MONITOR - Computer has a got a monitor or

display Unit that allows one to see whatever is being

done, when typing in word you will be able to see the

words, sentence as you type from the computer monitor,

a monitor is basically a electronic screen on which words,

numbers, texts, graphics and drawing can be viewed.

2. PRINTER - as an external output device that enables one

to output all relevant soft copies into a hardcopy materials

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like paper, basically printer print what you have in your

screen.

3. SPEAKERS - Speaker gives you a sound output if

connected to your computer, while other computers

comes with built in speakers some operate with external

speakers.

4. HARD DISK - a computer hard disk is also an output

device where one can store all the information in one

place.

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5. HEADPHONE - These are also computer output devices.

Headphones give sound output from the computer. They

are similar to speakers, except they are worn on the ears

so only one person can hear the output at a time.

6. FLOPPY DISKS - These were some of the original output

devices that were used to save data, but time has seen

them getting out of market for the newer output devices.

7. FLASH DISK - This is one of the portable output devices

that can be used in any computer as long as you have a

USB connection.

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8. COMPACT DISK - Some compact disks can be used to

put information on. This is called burning information to a

CD.

9. COMPUTER VCD - is the higher version of a CD does

output both audios and video files

10. Computer DVD - is a higher version of computer VCD

does output both audios and video files

7 INTERNAL DEVICES THAT CAN BE FOUND INSIDE

SYSTEM UNIT AND THEIR FUNCTIONS

1. MOTHERBOARD: The motherboard is the main

component of computer. It is a large rectangular board

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with integrated circuitry that connects the other parts of

the computer including the CPU, the RAM, the disk

drives(CD, DVD, hard disk, or any others) as well as any

peripherals connected via the ports or the expansion slots.

2. OPTICAL DRIVE: An optical drive is any storage device

that uses light to read and write information. Common

optical disc drives include CD, DVD, and Blu-ray drives. An

optical drive in a computer system allows you to use CDs,

DVDs, and Blu-ray discs to listen to music or watch a

movie.

3. POWER SUPPLY UNIT: A power supply unit (PSU)

converts mains AC to low-voltage regulated DC power for

the internal components of a computer.

4. HARD DISK DRIVE: A hard disk drive is a hardware

device that's used to store information like software and

files. Hard disk drives are the mechanism that reads and

writes data on a hard disk.

5. FLOPPY DRIVE: The floppy drive is the piece of computer

hardware that's used to read and write data on 3.5 or 5.25

inch floppy diskettes.

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6. CASE FAN: Alternatively referred to as a system fan, a

case fan is a fan located inside a computer case attached

to the front or back of the computer that helps bring air

into the case and also take hot air out of the case.

7. RAM: The Random-Access Memory (RAM) stores the

code and data that are being actively accessed by the

CPU.

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GENERATIONS OF COMPUTER

1. First Generation (1940-1956) Vacuum Tubes

The first computers used vacuum tubes for circuitry and

magnetic drums for memory, and were often enormous,

taking up entire rooms. They were very expensive to operate

and in addition to using a great deal of electricity, generated

a lot of heat, which was often the cause of malfunctions.

First generation computers relied on machine language, the

lowest-level programming language understood by

computers, to perform operations, and they could only solve

one problem at a time. Input was based on punched cards

and paper tape, and output was displayed on printouts.

2. Second Generation (1956-1963) Transistors

Transistors replaced vacuum tubes and ushered in the

second generation of computers. The transistor was invented

in 1947 but did not see widespread use in computers until

the late 1950s. The transistor was far superior to the vacuum

tube, allowing computers to become smaller, faster,

cheaper, more energy-efficient and more reliable than their

first-generation predecessors. Though the transistor still

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generated a great deal of heat that subjected the computer

to damage, it was a vast improvement over the vacuum

tube. Second-generation computers still relied on punched

cards for input and printouts for output.

3. Third Generation (1964-1971) Integrated Circuits

The development of the integrated circuit was the hallmark

of the third generation of computers. Transistors were

miniaturized and placed on silicon chips, called

semiconductors, which drastically increased the speed and

efficiency of computers.

Instead of punched cards and printouts, users interacted

with third generation computers through keyboards and

monitors and interfaced with an operating system, which

allowed the device to run many different applications at one

time with a central program that monitored the memory.

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