Learning About Parts of Computer

ADE100- Computer LiteracyLecture 02

Knowledge test

•What is computer?• Briefly explain role of Charles Babbage.•What is the purpose of input devices?•What is the role of Joystick & OCR?

Topics covered

• Input devices (contd.)• Interfacing with the computer using mouse & keyboard•Output devices• Storage devices •Understanding of Central Processing Unit (CPU)•How do computers work?

What is input?

• Any data or instructions used by a computer• Types of input:• Data- text form• Instructions- particular commands• Voice- audio signals through microphone• Image- inserting a picture

The Keyboard

•How keyboard works?• Keyboard controller (a tiny chip) detects

a key pressed and places a code into its memory called buffer (a temporary memory area).• Controller sends a code to the CPU• Code represents the key pressed

• Controller sends a signal to the operating system• Operating system responds• Controller repeats the letter if held

The Mouse

• Common mouse actions are:• Right click • Left click• Drag & drop• Move• Scroll • Double click

The Mouse

• Benefits• Pointer positioning is fast• Menu interaction is easy• Users can draw electronically

The Mouse

•Mouse button configuration• Configured for a right-

handed user• Can be reconfigured

• Left mouse button is called a primary button• Extra buttons are

configurable

• Procedure• Go to control panel• Double click mouse icon

Ergonomics and Input Devices• Ergonomics• Study of human and tool interaction• Concerned with physical interaction• Attempts to improve safety and comfort

Ergonomics and Input Devices•Repetitive Strain/Stress Injury (RSI)• Caused by continuous misuse of the body• Many professionals suffer from RSI

•Carpal Tunnel Syndrome (CTS)• Carpal tunnel is a passage in the wrist• Holds nerves and tendons• Prolonged keyboarding swells tendons

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Carpal Tunnel Syndrome

Ergonomics and Input Devices•Office hardware suggestions•Office chairs should have• Adjustable armrests and height• Armrests• Lower back support

•Desks should have• Have a keyboard tray• Keep hands at keyboard height• Place the monitor at eye level

Ergonomics and Input Devices• Techniques to avoid RSI• Sit up straight• Have a padded

wrist support• Keep your arms

straight• Keyboard properly• Take frequent

breaks

What is output?

• Processed data or information• Types of output• Text• Graphics like charts, graphs, pictures• Audio & video

•Output devices• Monitors• Printers• Speakers • Projectors

Monitors

• Known as screens or display screens•Output referred to as soft copy • Categorized by color output• Monochrome• One color with black background

• Grayscale• Varying degrees of gray

• Color• Display 4 to 16 million colors

Measuring quality of monitors

• Resolution• Refers to sharpness & clearness of image• More no. of pixels means high resolution• E.g. 800x600 means 800 horizontal, 600

vertical

•Dot pitch• Distance between each pixel on screen• It also determines picture clarity• Smaller distance b/w pixels shows higher

sharpness of image

Measuring quality of monitors

• Refresh rate• No. of times per second the electron gun

scan every pixel on the screen• Measured in Hertz (Hz) or Cycles per

second• Pixels fade after some time so need to

refresh• Normally 75 times per second

• Size• Measured diagonally in inches• Distance from corner to corner• Different sizes like 14, 15, 17, 21, 22

inches.

Types of monitors

• Cathode-ray tube monitors or CRTs• Flat-panel• Liquid crystal display (LCD)• Portable and thinner than CRTs

•Other monitors• E-books• Data projectors• High-definition television (HDTV)

Printers

• Translates information that has been processed by the system unit•Output referred to as hard copy• Features• Resolution• Color capability• Speed• Memory

More on printers

• Ink-jet printer• Use ink/cartridge• Both black & color

• Laser printer• Personal laser printers• Shared laser printers

•Other printers• Dot-matrix• Plotters• Photo printers

Audio output devices

• Translates audio information into sounds that people can understand• Sound card• Between CPU & speakers• Converts digital signals to analog

• Common devices• Speakers• Headphones

Data projectors

• Project image onto wall or screen• LCD projectors• Most common type of projector• Small LCD screen• Very bright light• Require a darkened room

•Digital Light Projectors• A series of mirrors control the display• May be used in a lighted room

Combined I/O devices

• Fax machines•Multifunction devices•Digital camera• Internet telephones• Terminals• Keyboard and monitor

Storage devices

• Store data when computer is ON/OFF• Two processes• Writing data• Reading data

• Primary storage devices• RAM & ROM

• Permanent storage devices• Magnetic storage devices• Optical storage devices• Mobile storage devices

Primary storage

• RAM• Random Access Memory• Stores open programs and data• Small chips on the motherboard• More memory makes a computer faster• 512MB, 1GB up to 4GB

• ROM• Read Only Memory• ROM-BIOS

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Computer RAM and CPU- Right click My Computer

- Select properties from menu

Secondary storage devices

• Stores data when computer is OFF• Three types• Magnetic storage devices• Hard disk drives, floppy disks,

• Optical storage devices• CD, DVD

• Mobile storage devices• Online storage• Flash memory• Memory cards

Magnetic storage

•Data organization• Disks must be formatted before use• Format draws tracks on the disk• Tracks is divided into sectors• Amount of data a drive can read

Magnetic storage

•Hard disk drive• Secondary storage device in a computer• 2 or more aluminum platters• Each platter has 2 sides• Spin between 5,400 to 15,000 RPM• Data found in 9.5ms or less• Drive capacity greater than 40 GB

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Optical storage devices

• CD-ROM (Compact Disk Read Only Memory)• Read using a laser

• Lands, binary 1, reflect data• Pits, binary 0, scatter data

• CD speed is based on the• Original CD read 150 Kbps• A 10 X will read 1,500 Kbps

• Standard CD holds 650 MB

• CD-R (Compact Disk Recordable)• Write data once

• CD-R/W (Compact Disk Rewriteable)• Write data multi times

• Combo drive (CD R/W, DVD-R)

Optical storage

•DVD- (Digital Versatile Disk)• Digital Video Disk• Use both sides of the disk• Capacities can reach 18 GB• DVD players can read CDs

•DVD-R• DVD recordable once

•DVD-R/W• DVD Rewriteable multi times

• Super drive- (CD R/W +DVD R/W)

Mobile storage devices• Online storage• Dropbox, Google drive

• Flash memory• Found in cameras and USB drives• Combination of RAM and ROM• Long term updateable storage

• Smart cards• Credit cards with a chip• Chip stores data• Eventually may be used for cash• Hotels use for electronic keys

CPU- Central Processing Unit

•The CPU• Brain of the computer

•Components of CPU• Control unit• Controls resources in computer• Acts like Traffic Policeman

• Arithmetic logic unit• Simple math operations• Registers

Working of CPU

•Machine cycles• Steps by CPU to process data• Instruction cycle• CPU gets the instruction

• Execution cycle• CPU performs the instruction

• Billions of cycles per second• Multitasking allows multiple instructions

Information Processing Cycle

• Four steps followed to process data• Input• Processing• Output• Storage

Activity-20 minutes

• Practice the use of mouse by selecting different icons on your desktop or in My computer.• Briefly talk about different parts of a real

keyboard.• Detach and attach different input and output

devices of your computer.• Install a typing tutor on your computer from a

CD/DVD/internet. • Practice first lesson for 15 minutes.

Further reading

• “Introduction to Computers” by Peter Norton, 7th edition.• 1B- Looking inside the computer system• 2A- using the keyboard & mouse• 3A- Video & sound• 3B- Printing• 4A- Transforming data into information• 5A- types of storage devices

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ThanksEnd of Lecture 02

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Allah Hafiz