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Computer Awareness
What is Computer?
The word computer has originated from the Latin word Compute.
Compute means to calculate.
Computer is an electronic device.
It executes the instructions in a program.
Computer after data input, processes the data, produces output and stores the results.
What are the Components of a computer?
Input unit - It accepts data and instructions from the user.
It converts the accepted instructions into the machine language.
It gives converted instructions to CPU for processing.
 

What are Input devices?
Common input devices - Keyboard and Mouse
What is a Track Ball?
It is used as an alternate of mouse. The user moves its ball. This moves the pointer on the screen.
What is Joystick?
Input device which moves the cursor on the screen.
Widely used in Computer games
What is a Digital camera?
Digital camera captures images and records the videos. These are stored in files. These pictures, images and videos can be edited and copied on to computers.
What is a Microphone?
Microphone is an input device for sound. It converts sound into electrical signals.
Voice recognition software can be used to enter text in word processor application by using the microphone.
 

What is a Touch screen?
Touch screen is an input and output device and also a display screen.
On the screen text or pictures are displayed.
A user interacts by touching the screen.
When a touchscreen is used there may be no requirement of keyboard or screen.
These are widely used in smart phones, ATM machines and other equipments.
What is a Digital Video?
Digital Video stores images from video camera or television in a digital format. Digital videos are preferred over analog videos. And used in multimedia presentations.
What is a Scanner?
An image scanner is an electronic device.
It optically scans images, object, text, pictures or handwriting and converts it to a digital image.
It is similar to photocopier machine but makes digital copy of an image.
What is a Graphic tablet?
A graphic tablet is a computer input device
A user can write text, draw pictures, images, animations and graphics, with a special pen like input device.

What is a Keyboard?
Keyboard is the most commonly used input device in computer.
There are three types of keys on the keyboard
Alphanumeric keys, special keys and function keys.
Alphanumeric keys
Alphabets from A to Z
Digits - 0 to 9
Different characters such as space.
Special keys include
alt
backspace
caps lock
ctrl
delete
enter
shift, etc.
Function Keys
Keys from F1 to F12 in the keyboard
What is a Mouse?
An electronic input device.
Mouse controls the movement of the cursor or pointer on a display screen.
Mouse - without cord or wire is called a wireless or cordless mouse.

What is an Output Unit?
It accepts processed data from CPU. It converts results from machine language into simple language and displays results to user. It prints results on paper or other permanent media.
What is Types of output?
Hard copy Printed on paper – Hard Copy
Displayed on screen – Soft Copy
What is an Output Device? 
The means through which computer gives output are known as output devices
What is a Common Output Device?
Monitor
Display screen of computer.
Visual Display Unit of Computers
 

What is a Printer?
Printer is an external hardware or output device.
Printer gives the output in printed format (usually on paper) after receiving data from computer
An external device used with computer that prints image, text or photo.
What are the Types of printers?
Daisy-Wheel
Dot-Matrix
Ink-Jet
Laser
LCD& LED
Thermal Printer
Speed of printers in measured in
cps - characters per second
ppm- pages per minute

What is a Projector?
Projector is that hardware and output device
It projects an image on the flat surface like computer screen.
Projectors are commonly used in presentations, meetings, seminars education and training.
What is a Sound Card?
Also known audio card.
 Sound card enables computer to produce sound through speaker or head phone.
What is a Speaker?
It is a hardware device.
Speaker presents the sound produced during any program.
This is connected to sound card.
What is Video Card or Graphics Cards?
This is an internal circuit board
It allows the image to be displayed on the monitor.
 

What is a Memory Unit?
It temporarily or permanently holds the data received from the input device.
It holds the data being processed and intermediate results being generated.
It holds the system software and the application software in use.
Computers memory is mainly classified into two types.
What is a Random Access Memory?
All active programs and data are stores in RAM
They may readily available and easily accessed by the CPU.
What is a Read Only Memory?
The data stored on ROM cannot be changed.
It is non-volatile.
ROM can keep its contents even without a power source.
The number of bytes it can store determines the storage capacity of a memory.

What is a Write Time?
The time taken to write a word.
Access Time of the Memory
The time to retrieve information
What is a Secondary / Auxiliary Storage?
Auxiliary storage holds what is not currently being processed.
It is used for input-data and programs.
What is a Magnetic Tape?
It is a magnetically coated strip of plastic.
It is data storage medium.
Tapes are sequential-access media
What is a Floppy Disk?
It is a flexible circular disk of diameter 3.5 inches.
It is made of plastic coated with a magnetic material.
.

What is a Hard Disk?
Hard disks have large storage capacity.
These are rigid and less portable than floppies and disks
These are found in desktops computers and laptops.
They are less portable than floppies
What is a Zip Disk?
They are slightly larger than the conventional floppy disks and can hold 100 MB of data
What is a Jaz Disk?
They are removable disk drives and can hold 1 GB of data
What is an Optical Disk?
They are storage medium.
From these data is read and to which it is written using lasers.
They can store much more data up to 6 gigabytes than magnetic media as floppies and hard disks
 

What is a CD-Rom?
It is a type of optical disk.
It is capable of storing large amounts of data up to 1 GB
They cannot be erased and filled with new data after it is once recorded.
What is a DVD?
DVDs are digital versatile disks.
They are the high density disks
Can hold upto 17 GBs of data on both its platters.

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