Computer Hardware & ProcessingOutside the Box
CSA 1051.0
September 7, 2010
Computers Are Data-Processing Devices
• A computer’s four major functions:– Gathers data (users input data)– Processes data into information– Outputs data or information– Stores data and information
• Plus– Computers can communicate with other
computers
Data vs. Information
• Data: Representation of a fact, figure, or idea • Information: Organized, meaningful data
Bits and Bytes: The Language of Computers
BitBinary digit0 or 1Abbreviation “b”
Byte8 bitsAbbreviation “B”
Each letter, number, and character is a string of eight 0s and 1s
Counting BytesName Abbreviation Number of Bytes Relative Size
Byte B 1 byte Can hold one character of data.
Kilobyte KB 1,024 bytes (210 bytes) Can hold 1,024 characters or about half of a double-spaced typewritten page.
Megabyte MB 1,048,576 bytes (220 bytes) Can hold approximately 768 pages of typed text.
Gigabyte GB 1,073,741,824 bytes (230 bytes) Approximately 786,432 pages of text; 500 sheets of paper is approximately 2 inches, so this represents a stack of paper 262 feet high.
Terabyte TB 1,099,511,627,776 bytes (240 bytes) This represents a stack of typewritten pages almost 51 miles high.
Petabyte PB 1,125,899,906,842,62 bytes (250 bytes) The stack of pages is now 52,000 miles high, or approximately one-fourth the distance from the Earth to the moon.
Exabyte EB 1,152,921,504,606,846,976 bytes (260 bytes)
The stack of pages is now 52 million miles high, or just about twice the distance between the Earth and Venus.
Zettabyte ZB 1,180,591,620,717,411,303,424 bytes (270 bytes)
The stack of pages is now 52 billion miles high, some 20 times the distance between the Earth and Pluto.
Computer Hardware & Computer Software
Computer Hardware• Anything you can kick
Computer Software• Intangible instructions that
tell the hardware what to do.– Systems Software– Applications Software
Basic Computer Hardware Components
• System Unit – everything in the box– Motherboard, CPU, memory
• Peripheral Devices – everything outside of the box– Keyboard, mouse, monitor, printer
• Storage Devices – where data/information gets stored– Hard drive, CD/DVD, flash drive, memory cards
Input Devices
• Translates what humans understand into a format the computer understands
• Different types of devices for different types of data– Keyboard– Mouse/pointing device– Microphone – Scanner– Digital camera– Stylus
Keyboards
• Used for entering text and commands.• The QWERTY layout is standard on most PCs.• Enhanced keyboard features include number,
function, and navigation keys.• Notebook keys are smaller and use a function key to
expand functionality.
So what is this??
More Specialty Keyboards
• Virtual laser keyboard • Configurable keyboard
Point and Draw Devices
• Optical mouse– Needs no mouse pad– Doesn’t need cleaning
• Trackball– Easier on wrists– Stays stationary on desk
More Point and Draw Devices
• Wireless mouse– Uses radio or light waves
• Touchpad– When a mouse just
won’t do
Other Text and Command Input Devices
• Game controllers• Touchscreens• Digital pens
Image Input DevicesDigital cameras, camcorders, and cell phones
• Still images• Video
Webcams• Live video
Sound Input Device
• Microphones are used for:– Podcasts– Video-conferencing– Internet phone calls– Speech recognition
Output Devices
Convert what the computer understands into a format that humans understand
Output can be in two formats
Hardcopy – tangiblePrintouts
Softcopy – in tangibleVideo, sound, images on monitors
LCD Monitors
• LCD – Liquid Crystal Display• Screens are grids made up
of millions of pixels• Each pixel is represented
by a bit pattern comprised of a combination of red, green, and blue
• Liquid crystal is sandwiched between two transparent layers to form images
LCD Monitor Characteristics• Resolution – total number of pixels, can be changed• Screen size
– 21” monitor - 1680x1050 pixels– 19” monitor - 1440x900 pixels or 1280x1024 pixels– Wide screen vs. standard 4:3 ratio
• Viewing angle – visibility from the side • Contrast ratio – brightest white to darkest black• Brightness – greatest amount of light when displaying
pure white• Response time – time it takes for a pixel to change
color
Printer Categories
• Impact printers – Dot-matrix
• Nonimpact printers– Inkjet– Laser
• Specialty printers– All-in-one– Plotters– Thermal
Nonimpact Printers
Inkjet• Less expensive device• Print high-quality color
images cost effectively
Laser• More expensive device• Faster printing speed• Color lasers are becoming
less expensive
Printer Characteristics
• Speed (ppm)
• Resolution (dpi)
• Color output
• Memory
• Use and cost
• Cost of consumables
Storage Devices• Non-volatile
– Almost permanent• Types of computer storage devices
– Internal hard drive– USB flash drive – Memory cards– Optical drive– External hard drive– Online storage
• Secondary storage
Hard Drive• May be internal or
external– Internal is faster
• Storage capacity is up to 2 terabytes (TB)
• Access time is measured in milliseconds
• Data transfer rate is measured in megabits or megabytes per second
How a Hard Drive Works
Composed of coated platters stacked on a spindle
Data saved to the disk: Pattern of magnetized spots– Spots = 1– Spaces = 0
Spots are translated into data
Optical Storage
• Optical media: Store data as tiny pits burned into a disc by a laser– Pre-recorded
• CD-ROM, DVD-ROM, BD-ROM– Recordable
• CD-R, DVD-R, BD-R– Rewritable
• CD-RW, DVD-RW, BD-RE
• Uses a burner to write to optical media• Uses two lasers to read optical media
Flash Memory
• Flash / thumb drive• Memory cards• Electron grid / gates• High storage capacity• Use very little power• Must unmount before removing from
computer• Can cause security concerns
Online Storage
• Data stored on the Internet• Inexpensive• Data backup• Can access data anywhere• Can be password protected
All Storage Media Will Fail
Back up your data!