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01computers and input and output devices

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					      CHAPTER 1COMPUTERS AND INPUT AND OUTPUT DEVICES

STRUCTURE:

1.1
1.2      WHAT IS A COMPUTER?
1.2.
1.3.
1.4.     WHAT IS COMPUTER HARDWARE?
1.3.

WHAT IS AN INPUT DEVICE?


1.4.     EXERCISE 1

1.5.     WHAT IS AN OUTPUT DEVICE?
1.6.     EXERCISE 2
1.7.     WHAT DO WE MEAN BY STORAGE DEVICES?
1.8.     EXERCISE 3
1.9.     EXERCISE 4
1.10.    WHAT IS THE FIXED MEDIA?

This Lesson introduces you to the computer and input and output devices.

1.1      What is a Computer?

         A Computer is fundamentally a machine that does three things –
       Accepts structured inputs.
      2. Processes these as per prescribed rules, and
      3. Produces a result as an output.

Broadly you can categorize computers into Computer Hardware and Software.

One generally hears the term PC. What is a PC? A PC actually refers to a Personal
Computer regardless of brand or type. It may be a HP, Wipro, and Compaq.

1.2.     What is Computer Hardware?

         Broadly stated Computer hardware is any part of a computer that you can
         physically touch and is physically attached to a computer.

For example: a keyboard, a monitor, a system unit and a mouse to name a few.

Hardware can be categorized into input-output devices and storage devices.


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1.3.   What is an input device?

A device whose purpose is to allow the user to provide input or information to a
computer system is called an Input device.

There are various such devices like Keyboard, mouse, joystick, touch screens and pen
devices.
We will be mainly using the keyboard. We have a special mouse but that is also through
the keyboard.
Keyboards have different Layout, mainly the 101 keyboards or 104 keyboards. The 3
additional keys on a 104 Keyboard are the 3 Start Button keys. So one can say that the
104 Keyboard was designed for Windows.

Nowadays we are also seeing different keyboards especially for the Internet, etc.

1.4.   Exercise 1:

Help them feel the shape of the keyboard. Tell them to pull out the draw at the below the
tabletop and feel the cable that attaches the keyboard to the System Unit.

1.5.   What is an output device?

An output device is one whose purpose is to show us the results of processing.
Examples of this are Monitor, printers, Braille displays, speakers that emit sound

1.6.   Exercise 2:
1.7.   What do we mean by storage devices?
1.8.   Lets feel the monitor and find the On/Off Button for the Monitor

We will be teaching you to use a printer and about different types of printers at a latter
stage.

1.7.   What do we mean by storage devices?

Storage devices refer to removable or fixed.

Removable Media:
Some of the removable media’s are Floppy Disks, CD-ROMs.

The Floppy Disk is a removable media that can be transported with you. Floppy Disks are
inserted in a Floppy Disk Drive. They are generally referred to as A drive (A:) or B drive
(B:)




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Floppy Disk used is mainly of 2 types 5 1/4" FDD or 3 1/2" FDD. 5 1/4" FD store 1.2MB
of data and 3 1/2" FD store either 720K or 1.44MB depending on the type of disk but
generally it is 1.44 MB of space. Lately 3 1/2" FD are being used.

1.8.   Exercise 3:

Show the 2 types of floppies and help them to insert them in the specific drives and eject
them.

Another type of removable media is CD-ROM. We insert a CD-ROM into a CD-ROM
Drive. A CD-ROM is a read only media as in you can't store data on it yourself, we can
only read from it. CD-ROM stands for Compact Disc Read Only Memory. The name in
itself explains that you can only read from this type of media.

To write onto CDs, we need a CD Writer.

We have all heard of CD's, they can either be music CDs or data CDs. On our computer
we can play a music CD too as we do in our music systems. Data CDs on the other hand
can only be played on Computer CD-ROM drives.

The first button from the right side is generally the open/close button on the CD-ROM
Drive.

1.9.   Exercise 4:

Let’s eject the CD-ROM Drive, insert the CD and close the CD-ROM Drive


1.10. What is the Fixed Media?
The Hard disk drive (HD) is a fixed media in which data is stored. The HDD is generally
referred to as the C drive or C: HD is measured in Megabytes or Gigabytes like the
machine we are on has a 2.1 Gigabyte HD. The hard disk is basically a lot larger than
Removable media in capacity and at least 10 times faster than floppies. The reading
writing speed of the hard disk varies from hard disk to hard disk.

All the storage devices that is the Hard Disk, the Floppy Disk Drive and the CD-ROM
Drive are installed in the system unit.




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