Slide 1
Computers Are Your Future
Chapter 7 and 8
Input/Output and Storage
© 200 Prentice-Hall, Inc Slide 2
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
© 200 Prentice-Hall, Inc Slide 3
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
© 200 Prentice-Hall, Inc Slide 4
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
© 200 Prentice-Hall, Inc Slide 5
Input Devices: Giving Commands
Keyboard
Mouse
Other Pointing
Devices
© 200 Prentice-Hall, Inc Slide 12
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)
© 200 Prentice-Hall, Inc Slide 13
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.
© 200 Prentice-Hall, Inc Slide 14
Digital CamerasDigital Video
Click on the
picture to play
the video.
Digital Input: Digital Cameras and
Digital Video
© 200 Prentice-Hall, Inc Slide 15
Scanners
Flatbed
Fax Machines
Alternative Input Devices
Barcode reader
© 200 Prentice-Hall, Inc Slide 18
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
© 200 Prentice-Hall, Inc Slide 19
Monitors
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)
Light Emitting Diode(LED TV)
Plasma TV
CRT
LCD LED Plasma
© 200 Prentice-Hall, Inc Slide 22
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)
Dot pitch- Distance between two pixel
© 200 Prentice-Hall, Inc Slide 23
Printers
A printer is a peripheral
device that produces a
physical copy or hard
copy of the computer’s
output.
DPI- Dot Per Inch
No of dots(pixel) on a
linear inch
© 200 Prentice-Hall, Inc Slide 24
Printer Videos
© 200 Prentice-Hall, Inc Slide 25
© 200 Prentice-Hall, Inc Slide 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.
© 200 Prentice-Hall, Inc Slide 27
WMA MIDI MP3 WAV
Beethoven
1:15 min
Rocky
2:56 min
Hornsby
48 sec
Cheers
15 sec
Click an icon
to play
music.
Click the icon
again to stop
playing.
Try clicking on
Cheers while
playing music.
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
© 2018 Prentice-Hall, Inc Slide 28
Hard Drive – storage RAM – memory
Memory vs. 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.
© 200 Prentice-Hall, Inc Slide 29
The Storage Hierarchy
The three levels of storage hierarchy are:1. Primary Storage(Main Memory)
RAM, ROM, Cache, Register
2. Secondary Storage
Hard disk, External Hard disk
3. Ternary Storage
Optical Disk
4. Offline Storage
USB Flash Drive, Memory Card
5. Cloud Storage
Google Drive, One Drive, icloud, Dropbox
© 200 Prentice-Hall, Inc Slide 30
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
© 200 Prentice-Hall, Inc Slide 31
Storage Devices
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
© 200 Prentice-Hall, Inc Slide 32
Sequential vs. 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
Tape Drive –
sequential storage
Hard Disk –
random-access storageFloppy Disk Drive –
random-access storage
© 200 Prentice-Hall, Inc Slide 33
Storage Technologies: Magnetic and Optical
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
Magnetic Storage Optical Storage –
CD/DVD drive
© 200 Prentice-Hall, Inc Slide 36
Floppy Disk Hard Drive CD ROM / DVD
Capacity – 720 KB to
1.44 MB
Access Time – 100ms
Capacity – Up to 1 TB
Access Time – 6 to 12ms
Capacity – CD-ROM 650
MB; DVD 17 GB
Access Time – 80 to 800ms
Storage Capacity and Speed
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
© 200 Prentice-Hall, Inc Slide 37
Platter Read/Write
head
Hard Disks
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.
© 200 Prentice-Hall, Inc Slide 38
Working of Hard disk
© 200 Prentice-Hall, Inc Slide 39
© 200 Prentice-Hall, Inc Slide 40
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).
Two types of hard disks
Internal Hard Disk
Located inside system unit
Used to store programs and data files
External Hard Disks
Removable hard disks
Used to complement internal hard disk with an unlimited amount of additional
storage
Capacities extend into the terabytes (TBs)
© 200 Prentice-Hall, Inc Slide 41
Solid State Drive
Optical Disks
Hold over 100 gigabytes (GB) of data
Attributes
Lands
Pits
Three types
Compact Disc (CD)
Digital Versatile Disc (DVD)
Blu-Ray (Hi-Def) Disc
Compact Disc (CDs)
Optical format
Capacity of 650 MB to 1 GB
Rotation speeds vary
Three basic types
Read only (CD-ROM)
Write once (CD-R)
Rewriteable (CD-RW)
Return
Digital Versatile Discs (DVDs)
Like CDs, but newer format called digital versatile
disc or digital video disc (DVD)
Capacity of 4.7 GB to 17 GB
Three basic types
Read only
(DVD-ROM)
Write once
(DVD+R and DVD-R)
Rewriteable
(DVD+RW, DVD-RW, and DVD-RAM)Return
Blu-ray Disc (BDs)
Next generation optical disc for recording high-
definition (hi def) video
Capacity of 25 GB to 100 GB
Blu-ray optical drives are usually capable of reading
standard DVDs and CDs in addition to Blu-ray discs
Return
Optical Disk Comparison
© 200 Prentice-Hall, Inc Slide 47