1. Recap of Lecture 02 Generations of Computer Types of Computers
Classifications of Computers

2. INTRODUCTION TO Computer
Lecture No 3
Computer Hardware
Manual & Automatic Input Devices
Output Devices

3. Computer Hardware
Hardware are the electronic and mechanical components of a computer systems.
Physical components and which can be touched, handle or seen physically.
Despite the difference in performance among the different kinds of computers, every digital computer is made up of four basic units,
Input Unit (Input Devices are used to enter data into the Computer)
Out Put Unit (Out Devices are used to see the result of Processed Data )
Central Processing Unit (CPU)
Secondary Storage

4. Organization of Computer.
Auxiliary Storage
Input
Units
Output
Units
Main Memory
&
CPU
(Central Processing Unit)

5. Input Unit
The initial unit which provides communications between the user and the computer is the input unit.
This unit describes a device used to transfer information into a computing system.
The devices used to give data or commands to computer are called Input devices.

6. Input & Output Devices

7. Input Devices
Data or information can be fed into computer by using different peripherals i.e. types of input devices.
Two types of input devices
Manual Input Devices
Automatic Input Devices

8. Manual Input Devices
A manual input device requires a human hand to control it…
Keyboard
Mouse
Camera
Scanner

9. Manual Input Devices Tracker ball Joystick
A manual input device requires a human hand to control it…
Tracker ball
Joystick

10. Manual Input Devices Device Uses Advantages Disadvantages Keyboard
The most common input device
You press keys to input data into the computer
The most common type of keyboard is the QWERTY keyboard
People are familiar with keyboards, so they don’t need to be trained
Skilled typists can work very quickly
They are very reliable and cheap
Many people cannot type and look at the screen at the same time, so typing can be time consuming
Keyboard

11. Manual Input Devices Device Uses Advantages Disadvantages Mouse
Most common pointing device
Used to point and click on icons or menus
Combines well with a keyboard
Fast and accurate
Need a flat surface to use them
Mouse
A tracker ball is basically an upside down ball mouse.
The user runs their thumb over the ball to control the on-screen pointer
Useful where desk space is limited
Some people find that the thumb gets painful with prolonged use
Ball can get greasy and dirty
Tracker ball

12. Manual Input Devices Device Uses Advantages Disadvantages Joystick
Originally designed for pilots to control aeroplanes
Used to control wheelchairs and for playing games
They give a more realistic gaming experience when playing games such as flight simulators
Many different types available
Some people find them difficult to operate.
Joystick
Used to convert printed images or text into a file of digital data
Images can be edited before use
The quality of the final image is dependent on the original image
Scanner

13. Manual Input Devices Device Uses Advantages Disadvantages
Used for taking still images which can be uploaded to a computer for permanent storage
You can preview the image before pressing the shutter button
No film needed or development costs
Unwanted images can be deleted
When the drive is full, images need to be uploaded to a computer or deleted
Digital Camera
A pointing device, built into a laptop for convenience
Portable - built into the laptop
Small movements needed to move the cursor
Takes practice to master
Touchpad or Fingerpad

14. Automatic Input Devices
An automatic input device inputs data without the need for human intervention (once the device has been set up), e.g. MICR, OMR, barcode reader, webcam, microphone.
Microphone
Barcode reader
Webcam

15. Automatic Input Devices
Uses
Advantages
Disadvantages
Banks print important data on the bottom of cheques using magnetic ink
This ink is then read by a computer
Expensive to produce and print magnetic ink, and the reader is also expensive
Banks are the main user – very few other applications
Very quick and accurate processing of data – very low error rate.
Very secure as any attempt to change the numbers on a cheque will be ignored as the reader only recognises magnetic ink in the same font
MICR
Magnetic Ink Character Recognition

16. Automatic Input Devices
Uses
Advantages
Disadvantages
Used to mark multiple choice exam papers, National Testing Service (NTS) use OMR for paper checking .
Very fast method of reading data, which save time.
More accurate than human data entry
Sometimes incomplete marks are not read correctly
OMR
Optical
Mark Recognition

17. Automatic Input Devices
Uses
Advantages
Disadvantages
Used to identify products in shops
The code is read by a barcode scanner which identifies the product name, product size/weight manufacturer name
Very quick and accurate way to enter data – suits busy shops
Prices changes are made on the database, not the barcode
All barcodes need to be programmed into the computer in advance
Barcode Readers

18. Automatic Input Devices
Uses
Advantages
Disadvantages
Used to input sound into the computer
Used to give the computer commands, or to dictate letters directly to a word processor
Very cheap piece of equipment
Helpful for people with additional needs or for busy people who need very quick letters
Computer can misread voice instructions due to natural variations in people’s voices
Microphone
Used to input moving images into the computer for use in online communication
Very cheap piece of equipment
Enables people to see each other
The moving picture tends to flicker due to current limitations in data transfer
Webcam

19. Output Devices

20. Output Devices
An output device is used to display or use information that comes out of a computer system.
Output devices convert electrical signals from a computer system into…
Sound (speakers or headphones)
Images ,video & Text (screen or printer)

21. Output Devices
Monitor
Speakers
Printer
Headphones
Plotter

22. Output Devices Device Uses Advantages Disadvantages TFT Monitor
Take up very little space
Run very quietly and produce little heat
Use about a third of the energy of a CRT monitor
TFT Monitor
Thin Film Transistor monitors are more commonly known as flat screens or LCD screens
Easy to damage
Colour contrast on cheaper models is not as good as CRT monitors
Cathode Ray Tube is very old technology. Almost completely replaced by flat screen monitors
Reliable
Last for a very long time
Large
Can be heavy
Produce a lot of heat
Old technology
CRT Monitor

23. Output Devices Device Uses Advantages Disadvantages Plotter
When connected to a computer through a sound card, music can be played
Gives feedback to user during general computer use
Speakers are not useful in a network room, as everyone would disturb each other
Headphones can be uncomfortable with extended use
Games are a lot more involving and realistic with sound
Speakers
& Headphones
These are specialist printers that can produce high quality printouts on large pieces of paper
Very high quality printouts
Almost any size paper can be used
Slower than normal printers
Expensive
Plotter

24. Printers There are 3 main types of printer… Device Uses Advantages
Disadvantages
Inkjet
General purpose use for family or home office
Cheap to buy
Latest models can be very fast
Ink cartridges can be very expensive
Laser
Business use for letters, stationery and images
Quality printing
Good for large areas of colour
Quiet & Quick
More expensive to buy than inkjets
Toner cartridges are expensive
Can make a carbon copy
Can print on continuous rolls of paper
Noisy and rather old-fashioned technology
Poor quality and only prints in black ink
Dot Matrix
Business use for duplicate documents

25. Soft copy
The result (text/graphics ) appear on displayed screen are known as soft copy and will disappear if display is switched off.
Therefore this form of output is not permanent and can be removed, changed or corrected.
Output devices used for soft copy:
Visual display unit (monitor or TV screen)

26. Hard copy
The results (text/graphics) printed on paper is known as Hard Copy.
It is considered as permanent copy and can be retained even computer is turned off.
Output devices used for Hard copy:
Printer
Plotters

27. Summary Introduction to Computer Hardware Input Unit ,Out Put Devices.
Different Types of Manual & Automatic Input Devices
Out Put Devices
Soft Copy
Hard Copy