1. Computers Are Your Future
© 2005 Prentice-Hall, Inc.

2. Computers Are Your Future
Chapter 5
Input/Output and Storage
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3. What You Will Learn About
The purpose of special keys and the most frequently used pointing devices
Input devices used to get audio and digital data into the computer
The characteristics of a monitor’s quality and the various types of monitors
The two major types of printers
The difference between memory and storage
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4. What You Will Learn About
The categories of storage devices
The performance characteristics of hard drives
How data is stored on both hard and floppy disks
The various optical storage media available for personal computers
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5. Input Input is any data entered into the computer’s memory.
Types of input include:
Data – Unorganized information (words, numbers, images, or sounds) that the computer converts to meaningful information
Software – Programs transferred from storage devices to the computer’s memory
Commands – Instructions that tell the computer what to do
Responses – Prompts requiring user feedback
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6. Input Devices: Giving Commands
Keyboard
Mouse
Other Pointing Devices
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7. Keyboard
The keyboard allows the computer user to enter words, numbers, punctuation, symbols, and special function commands into the computer’s memory.
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8. Types of Keyboards
Enhanced / Extended Keyboard
Ergonomic Keyboard
Enhanced or Extended keyboard – Typically 101 keys laid out in the QWERTY fashion; connected to the computer by a cable
Cordless keyboard – Uses infrared or radio wave signals
Ergonomic keyboard – Designed to help prevent cumulative trauma disorder (CTD) or damage to nerve tissues in the wrist and hand due to repeated motion
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9. The Mouse The mouse is the most widely used pointing device.
A mouse is palm sized.
As the mouse is moved, its movements are mirrored by the on-screen pointer.
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10. Types of Mice
Wheel Mouse
Cordless Mouse
Wheel mouse – Contains a rotating wheel used to scroll vertically within a text document; connects to PS/2 port or USB port
Cordless mouse – Uses infrared signals to connect to the computer’s IrDA port; it must be within sight of the receiving port
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11. Using the Mouse Mouse buttons enable the user to initiate actions.
Clicking (left-, right-, or double-clicking) allows the user to select an item on the screen or open a program or dialog box
Click and drag – Holding down the left mouse button and moving the mouse enables the user to move objects on the screen
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12. Other Types of Pointing Devices
Touch Screen
Trackball
Pointing Stick
Joystick
Pen
Touch Pad
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13. Audio Input Computers can accept input from a microphone.
An expansion card called a sound card records and plays back sound files.
Sound files contain digitized sound data.
Popular sound file formats include:
Windows WAV
Moving Pictures Expert Group (MPEG)
MP2 and MP3
Musical Instrument Digital Interface (MIDI)
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14. Audio Input: Speech Recognition
Speech recognition is a type of input in which the computer recognizes words spoken into a microphone.
Special software and a microphone are required.
Latest technology uses continuous speech recognition where the user does not have to pause between words.
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15. Digital Input: Digital Cameras and Digital Video
Click on the picture to play the video.
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16. Alternative Input Devices
Fax Machines
Scanners
Flatbed
Barcode reader
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17. Digital Cameras
The image’s light falls on a charge-coupled device (CCD) which transforms the light’s patterns into pixels (individual dots).
Images are stored in the camera using flash memory. The most popular types are CompactFlash and SmartMedia.
Photo-editing programs enable the user to edit the images.
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18. Digital Video
A video capture board transforms analog video into digital video.
Digital video cameras use digital technologies to record video images.
A Web cam is a low resolution video camera.
Digital video camera
Web cam
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19. Output Devices: Engaging our Senses
Output devices are peripheral devices that enable us to view or hear the computer’s processed data.
Visual output – Text, graphics, and video
Audio output – Sounds, music, and synthesized speech
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20. Monitors
CRT
LCD
A monitor is a peripheral device which displays computer output on a screen.
Screen output is referred to as soft copy.
Types of monitors:
Cathode-ray tube (CRT)
Liquid Crystal Display (LCD or flat-panel)
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21. Cathode-ray tube (CRT)
Resemble televisions
Use picture tube technology
Less expensive than a LCD monitor
Take up more desk space and use more energy than LCD monitors
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22. Liquid Crystal Display (LCD)
Cells sandwiched between two transparent layers form images
Used for notebook computers, PDAs, cellular phones, and personal computers
More expensive than a CRT monitor
Take up less desk space and use less energy than CRT monitors
Types of LCD monitors:
Passive-matrix LCD
Active-matrix LCD
Gas plasma display
Field emission display
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23. Monitor Specifications
Screen size – The diagonal measurement of the screen surface in inches (15, 17, 19, 21)
Resolution – The sharpness of the image determined by the number of horizontal and vertical dots (pixels) that the screen can display (800 x 600, 1024 x 768, 1600 x 1200)
Refresh rate – The speed at which the screen is redrawn (refreshed) and measured in Hertz (Hz) (60Hz, 75Hz)
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24. Printers
A printer is a peripheral device that produces a physical copy or hard copy of the computer’s output.
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25. Types of Printers
Laser
Inkjet
Inkjet printer, also called a bubble-jet, makes characters by inserting dots of ink onto paper
Letter-quality printouts
Cost of printer is inexpensive but ink is costly
Laser printer works like a copier
Quality determined by dots per inch (dpi) produced
Color printers available
Expensive initial costs but cheaper to operate per page
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26. Plotter
A plotter is a printer that uses a pen that moves over a large revolving sheet of paper.
It is used in engineering, drafting, map making, and seismology.
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27. Audio Output: Sound Cards and Speakers
Audio output is the ability of the computer to output sound.
Two components are needed:
Sound card – Plays contents of digitized recordings
Speakers – Attach to sound card
Click an icon to play music.
Click the icon again to stop playing.
Try clicking on Cheers while playing music.
WMA
MIDI
MP3
WAV
Beethoven 1:15 min
Rocky 2:56 min
Hornsby 48 sec
Cheers 15 sec
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28. Memory vs. Storage
RAM – memory
Hard Drive – storage
Storage, also known as mass media or auxiliary storage, refers to the various media on which a computer system can store data.
Storage devices hold programs and data in units called files.
Memory is a temporary workplace where the computer transfers the contents of a file while it is being used.
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29. Why Is Storage Necessary?
Storage devices:
Retain data when the computer is turned off
Are cheaper than memory
Play an important role during startup
Are needed for output
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30. Storage devices are categorized by:
The type of operations they perform
The method they use to access the information
The technology they use
Their location in the storage hierarchy
Their capacity and speed
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31. Sequential vs. Random Access Storage
Hard Disk – random-access storage
Tape Drive – sequential storage
Floppy Disk Drive – random-access storage
Sequential – Storage devices that read and write data in a serial (one after the other) fashion
Random-Access – Storage devices that read and write data without going through a sequence of locations
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32. Storage Technologies: Magnetic and Optical
Optical Storage – CD/DVD drive
Magnetic Storage
Magnetic – Storage devices use disks or tapes that are coated with magnetically sensitive material
Optical – Storage devices that use laser beams to read patterns etched into plastic disks
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33. Magnetic Disk Storage
A disk is formatted; it is divided into tracks and sectors, and a file allocation table (FAT) is created.
Track – circular band
Sector – pie shaped section
Cluster – two or more adjacent sectors
FAT – keeps track of specific locations of files
Track
Sector
Cluster
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34. Optical Disk Storage
Disk surface magnified
Cross-section of a disk
Microscopic indentations called pits scatter the laser beam’s light. A light-sensing device receives no light from the pits. A signal is sent to the computer corresponding to a 0 in the binary system.
Flat, reflective areas, called lands, bounce the light back to the light sensing device, which sends a signal corresponding to a 1.
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35. The Storage Hierarchy The three levels of storage hierarchy are:
Online storage – Also called primary storage, it is made up of the storage devices that are actively available to the computer system. User action is not required.
Near-online storage – Also called secondary storage, it is not readily available to the computer system. The user performs an action, such as inserting a disk, to make it available.
Offline storage – Also called tertiary storage or archival storage, it is not readily available to the computer system. Devices such as tape backup units store data for archival purposes.
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36. Storage Capacity and Speed
Floppy Disk
Hard Drive
CD ROM / DVD
Capacity – CD-ROM 650 MB; DVD 17 GB
Access Time – 80 to 800ms
Capacity – 720 KB to 1.44 MB
Access Time – 100ms
Capacity – Up to 80 GB
Access Time – 6 to 12ms
A storage device’s performance is measured by:
Capacity – The number of bytes of data that a device can hold
Access Time – The amount of time, in milliseconds (ms), it takes the device to begin reading data
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37. Hard Disks Hard disks are high-speed, high-capacity storage devices.
Platter
Read/Write head
Hard disks are high-speed, high-capacity storage devices.
They contain metal disks called platters.
They contain two or more stacked platters with read/write heads for each side.
Hard disks can be divided into partitions to enable computers to work with more than one operating system.
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38. Factors Affecting a Hard Disk’s Performance
Seek time or positioning performance – How quickly the read/write head positions itself and begins transferring information. It is measured in milliseconds (ms).
Spindle speed or transfer performance – How quickly the drive transfers data. It is measured in rotations per minute (RPM).
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39. Floppy and Zip Disks and Drives
Zip Drive
Floppy Drive
Click on the picture to see it work.
Floppy Disk
A disk or diskette is a portable storage medium.
High-density floppy disks that are commonly used today store 1.44 MB of data.
Disks work with a disk drive.
Zip disks store up to 750 MB of data and are not downwardly compatible with floppy disks.
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40. CD-ROM Discs and Drives
CD-ROM stands for Compact Disc-Read Only Memory.
CD-ROM drives can not write data to discs.
They are capable of storing 650 MB of data.
They are used for storing operating systems, large application programs, and multimedia programs.
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41. CD-R and CD-RW Discs and Recorders
Discs can be read and written to
Discs can only be written to “once”
CD-R drives are capable of reading and writing data
CD-RW
Discs can be read and written to
Discs are erasable
Discs can be written to many times
CD-RW drives are capable of reading, writing, and erasing data
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42. DVD-ROM Discs and Drives
DVD stands for Digital Video Disc.
DVD technology is similar to CD-ROM technology.
DVDs are capable of storing up to 17GB of data.
The data transfer rate of DVD drives is comparable to that of hard disk drives.
DVD-R and DVD-RW drives have the ability to read/write data.
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43. Solid State Storage Devices
Solid state storage devices use nonvolatile memory chips to retain data.
They do not have moving parts.
They are small, lightweight, reliable, and portable.
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44. Solid State Storage Devices
Smart Card
Memory Stick
Compact Flash Memory
Flash Memory
PC Card
Micro Drive
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45. Chapter 5 Summary
Input is the software, data, and information that is entered into the computer’s memory.
Input devices such as the keyboard, mouse, and trackball enable the user to enter data.
A pointing device enables the user to control movements of an on-screen pointer.
Speech recognition software enables the user to enter data into a computer by speaking into a microphone.
Video and images can be entered into a computer by way of digital cameras, scanners, and fax modems.
Monitors enable the user to view the computer’s processed data. The output is known as soft copy.
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46. Chapter 5 Summary (continued)
The two types of monitors are the CRT and the LCD.
A monitor’s quality is measured by screen size, resolution, and refresh rate.
Printers produce permanent versions (hard copies) of the computer’s output.
The two basic types of printers are the inkjet and laser.
Memory makes software and data available for the CPU’s use.
Storage devices are categorized by:
Data access (sequential or random-access)
Technology (magnetic, optical, or solid state)
Hierarchy (online, near-online, or offline)
Operations (read-only or read/write)
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47. Chapter 5 Summary (continued)
A hard disk’s performance is measured by its positioning performance and transfer rate.
Optical storage devices include:
CD-ROM– Read-only
CD-R– Record once
CD-RW– Erasable, write repeatedly
DVD-ROM– Read-only
DVD-R– Read/write
Solid state storage devices include:
PC cards
Flash memory cards
Smart cards
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