Recap of Lecture 02Recap of Lecture 02 Generations of Computer Types of Computers Classifications of Computers
INTRODUCTION TO Computer INTRODUCTION TO Computer
Lecture No 3
Computer Hardware
Manual & Automatic Input Devices
Output Devices
Computer HardwareComputer 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
Organization of ComputerOrganization of Computer
.
Main Memory&
CPU(Central Processing Unit)
InputUnits
OutputUnits
Auxiliary Storage
Input UnitInput UnitThe 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.
Input & Output DevicesInput & Output Devices
Input DevicesInput DevicesData 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
Manual Input DevicesManual Input Devices A manual input device requires a human hand to
control it…
Mouse
Keyboard
Scanner
Camera
Manual Input DevicesManual Input Devices
Tracker ball
Joystick
A manual input device requires a human hand to control it…
Manual Input DevicesManual Input Devices
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
Uses Advantages DisadvantagesDevice
Manual Input DevicesManual Input Devices
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
Tracker ball
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
Uses Advantages DisadvantagesDevice
Manual Input DevicesManual Input DevicesUses Advantages DisadvantagesDevice
Scanner
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
Joystick Originally designed forpilots 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.
Manual Input DevicesManual Input Devices
Digital Camera
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
Touchpador Fingerpad
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
Uses Advantages DisadvantagesDevice
Automatic Input DevicesAutomatic 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
Webcam
Barcode reader
Automatic Input DevicesAutomatic Input Devices
MICR
MagneticInk Character Recognition
Banks print important data on the bottom of cheques using magnetic ink
This ink is then read by a computer
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
Expensive to produce and print magnetic ink, and the reader is also expensive
Banks are the main user – very few other applications
Uses Advantages DisadvantagesDevice
Automatic Input DevicesAutomatic Input Devices
OMROpticalMarkRecognition
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 humandata entry
Sometimes incomplete marks are not read correctly
Uses Advantages DisadvantagesDevice
Automatic Input DevicesAutomatic Input Devices
Barcode Readers
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
Uses Advantages DisadvantagesDevice
Uses Advantages DisadvantagesDevice
Microphone 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
Automatic Input DevicesAutomatic Input Devices
Webcam 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
Output DevicesOutput Devices
Output DevicesOutput 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)
Output DevicesOutput Devices
Monitor Speakers
Plotter
Headphones
Printer
Output DevicesOutput Devices
TFT Monitor
Thin Film Transistor monitors are more commonly known as flat screens or LCD screens
Take up very little space
Run very quietly and produce little heat
Use about a third of the energy ofa CRT monitor
Easy to damage
Colour contrast on cheaper models is not as good as CRT monitors
Uses Advantages DisadvantagesDevice
CRT Monitor
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
Output DevicesOutput Devices
Speakers& Headphones
When connected to a computer through a sound card, music can be played
Gives feedback to user during general computer use
Games are a lot more involving and realisticwith sound
Speakers are not useful in a network room, as everyone would disturb each other
Headphones can be uncomfortable with extended use
Uses Advantages DisadvantagesDevice
Plotter These are specialist printers that can produce high quality printoutson large piecesof paper
Very high quality printouts
Almost any size paper can be used
Slower than normal printers
Expensive
PrintersPrinters
There are 3 main types of printer…
Dot Matrix
Laser
Inkjet
Uses Advantages DisadvantagesDevice
General purposeuse for family orhome office
Cheap to buy
Latest modelscan be very fast
Ink cartridges can be very expensive
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
Business usefor duplicatedocuments
Can make a carbon copyCan print on continuousrolls of paper
Noisy and rather old-fashioned technology
Poor quality and only prints in black ink
Soft copySoft copyThe 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)
Hard copyHard 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
SummarySummary
Introduction to Computer Hardware Input Unit ,Out Put Devices. Different Types of Manual & Automatic Input
Devices Out Put Devices Soft Copy Hard Copy