Hardware Components

Input Devices -- "How to tell it what to do“
- A keyboard and mouse are the standard way to
interact with the computer. Other devices include
joysticks and game pads used primarily for games.

Output Devices -- "How it shows you what it is doing"
- The monitor (the screen) is how the computer
sends information back to you. A printer is also an
output device.

INPUT DEVICES:

The Mouse:

Used to ‘drive’ Microsoft Windows.

 

The Keyboard:

  The keyboard is still the commonest way of entering information into a computer.


Tracker Balls:
 an alternative to the traditional mouse
and often used by graphic designer.






Scanners:
  A scanner allows you to scan printed material
and convert it into a file format that may be
used within the PC.


Touch Pads:
A device that lays on the desktop and responds
to pressure.






 

Light Pens:
Used to allow users to point to areas on a
screen.



Joysticks:
Many games require a joystick for the proper
playing of the game.





OUTPUT DEVICES:
 
VDU:
The computer screen is used for outputting
information in an understandable format.
 











Printers:
There are many different types of printers.
In large organizations laser printers are
most commonly used due to the fact that
they can print very fast and give a very
high quality output. 
 

 
Plotters:
A plotter is an output device similar to a
printer, but normally allows you to print
larger images.


Speakers:
Enhances the value of educational and
presentation products.

Speech synthesisers:
Gives you the ability to not only to display
text on a monitor but also to read the text
to you.


Storage Devices -- "How it saves data and
programs“
- Hard disk drives are an internal,
higher capacity drive which also stores the
operating system which runs when you power
on the computer.


 

- "Floppy" disk drives allow you to save
work on small disks and take the data with
you.





Hard Disks:
Speed:

• Very fast!

• The speed of a hard disk is often quoted as "average access time" speed, measured in milliseconds. The smaller this number the faster the disk.

Capacity:
Enormous! Often 40/80 Gigabytes. A Gigabyte is
equivalent to 1024 Megabytes.
Cost:
Hard disks costs are falling rapidly and normally
represent the cheapest way of storing data.

Diskettes (Floppy Disks):
Speed:
           Very slow!
Capacity:

             Normally 1.44 Mbytes.
Cost:
          Very cheap.



CD-ROM Disks:
Speed: 
Much slower than hard disks. The original
CD-ROM speciation is given a value of 1x
speed, and later, faster CD-ROMs are
quoted as a multiple of this value.


 




Capacity:
Around 650 Mbytes and more 









DVD Drives
Speed:
Much faster than CD-ROM drives but
not as fast as hard disks.
Capacity:
Up to 17 Gbytes.
Cost:
Slightly higher than CD-ROM drives.