Learning About Parts of Computer ADE100- Computer Literacy Lecture 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

Carpal Tunnel Syndrome 11

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

Computer RAM and CPU - Right click My Computer - Select properties from menu 26

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, 7 th 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

Thanks End of Lecture 02 39

Allah Hafiz 40