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Slide 1
Week 3
Input/Output and Storage
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
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
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
Slide 5
Input Devices: Giving Commands
Keyboard
Mouse
Other Pointing Devices
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 WAVMoving Pictures Expert Group (MPEG)MP2 and MP3Musical Instrument Digital Interface (MIDI)
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.
Slide 14
Digital Cameras Digital Video
Click on the picture to play the video.
Digital Input: Digital Cameras and Digital Video
Slide 15
ScannersFlatbed
Fax Machines
Alternative Input Devices
Barcode reader
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
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)
CRT LCD
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)
Refresh rate – The speed at which the screen is redrawn (refreshed) and measured in Hertz (Hz) (60Hz, 75Hz)
Slide 23
Printers
A printer is a peripheral device that produces a physical copy or hard copy of the computer’s output.
PrintersImpact vs. Non-impact
Impact - These printers have a mechanism that touches the paper in order to create an image. There are two main impact technologies:Dot matrix PrinterCharacter PrinterLine Printer
Non-impact - These printers do not touch the paper when creating an image. Inkjet printers are part of this group, which includes: Inkjet LaserSolid ink Thermal wax Slide 24
Slide 25
Inkjet Laser
Types of Printers
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
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.
Slide 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
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.
Slide 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
Slide 30
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
Slide 31
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 storage
Floppy Disk Drive – random-access storage
Slide 32
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
Slide 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.
Slide 36
Floppy Disk Hard Drive CD ROM / DVD
Capacity – 720 KB to 1.44 MB
Access Time – 100ms
Capacity – Up to 80 GB
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
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.
Slide 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).
Slide 39
Floppy and Zip Disks and Drives
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.
Zip DriveFloppy DriveClick on the picture to see it work.
Floppy Disk
Slide 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.
Slide 41
CD-R and CD-RW Discs and Recorders
CD-R 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
Slide 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.
Slide 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.
Slide 44
Compact Flash Memory
Flash Memory
Smart Card
Micro Drive
Memory Stick
PC Card
Solid State Storage Devices
Slide 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.
Slide 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)
Slide 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-onlyCD-R– Record onceCD-RW– Erasable, write repeatedlyDVD-ROM– Read-onlyDVD-R– Read/write
• Solid state storage devices include:PC cardsFlash memory cardsSmart cards