Slide 1

Computer Skills1400 TQN

Level 1

Chapter 7 and 8

Input/Output and Storage

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Input Devices Output Devices Storage Devices

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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 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

Slide 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

Input Devices

• Input device captures information and translates it into a form that can be processed and used by other parts of your computer.

KeyboardsPointing devicesGame controllersScannersStylusesMicrophonesDigital camerasWeb cams

p. 5.130 Fig. 5-1 Slide 6

Input DevicesThe keyboard is the most common input device. Types of keyboards include:

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

p. 5.131 Fig. 5-2

                     

          

                     

          

SimNet Concepts Support CD: “Keyboards”

Enhanced / Extended Keyboard

Ergonomic Keyboard

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Keyboard

Alphanumeric Keys Numeric Keys Function Keys Arrow Keys

Combination Keys Keys (Ctrl, Alt, Shift)

Special Keys

Types of Input Devices

p. 5.131 Fig. 5-2

                     

          

                     

          

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Pointing Devices

Various pointing devices are available Types of pointing devices:

• MouseMechanical mouseOptical mouseWireless mouse

• Trackball• Touchpad• Pointing stick

p. 5.132 & P. 5.133 Fig. 5-3 & Fig 5.4

SimNet Concepts Support CD: “Mice”

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Game Controller

Game controllers are used mainly to play games Types of gaming devices

• Gamepads• Joysticks• Gaming wheels• Force feed

p. 5.134 Fig. 5-5

                     

          

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Specialized Input Devices

Other types of input devices include:• Scanners• Styluses• Microphones• Digital cameras• Web cams

p. 5.135 Fig. 5-6 Slide 12

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ScannersFlatbed

Fax Machines

Alternative Scanners

Barcode reader

Scanner

•Scanner is a light sensitive device that helps you copy or capture images, photos, and artwork that exist on paper. Types of scanners include:Flatbed

                                                                   

SimNet Concepts Support CD: “Scanners”Slide 14

Styluses

• Stylus is an input device consisting of a thin stick that uses pressure to enter information or to click and point

• Styluses are used with:PDAs Tablet PCsGraphics tablets

p. 5.135 Fig. 5-6

                                                                   

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Microphones

• Microphones are used to input audio

• Three main types of microphones are:Desktop microphonesHeadsetsDirectional microphones

• Speech recognition is increasingly being included in application software

                     

          

                                                                   

                     

          

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Digital Cameras

Digital cameras are used to: • Download images to a computer• Post pictures to the Web• Produce videos

Resolution is measured in megapixels

Higher the resolution, better the image quality, but the more expensive the camera

SimNet Concepts Support CD: “Digital Cameras” Slide 17

Web Cams

• Web cam is a video camera that can be used to take images for uploading to the Web

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Output Devices

Output devices take information within your computer and present it to you in a form that you can understand

Main output devices:MonitorsPrintersSpeakers

SimNet Concepts Support CD: “Overview of Output Devices” Slide 19

Slide 20

Joystick

Touch Pad

Touch ScreenTrackball

Pointing Stick

Pen

Other Types of Pointing Devices

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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)

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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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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.

Web camDigital video camera

Output Devices

Output devices take information within your computer and present it to you in a form that you can understand

Main output devices:MonitorsPrintersSpeakers

SimNet Concepts Support CD: “Overview of Output Devices” Slide 24

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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) LED: Light Emitting Diode Plasma

CRT LCD

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Cathode-ray tube (CRT)

Resemble televisions Use picture tube technologyLess expensive than a LCD

monitorTake up more desk space and

use more energy than LCD monitors

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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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Monitor Specifications

Screen size measured as a diagonal line across the screen – from corner to opposite corner (15,17,20)

Resolution the number of pixels displayed on the screen (the higher the resolution, the closer together the dots) 600*800

Pixels (or picture element) dots that make up the image on your screen

Dot pitch is the distance between the centers of a pair of like-colored pixels

Refresh rate the speed with which a monitor redraws the image of the screen, and is measured in hertz

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Printers

A printer is a peripheral device that produces a physical copy or hard copy of the computer’s output.

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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

Difference Between Dot.Matrx, Inkjet and Laser Printer

Dot Matrix

1. Very Cheep

2. Less quality

3. 20-30 sec-A4

4. Less Maintenance cost

InkJet

1. More cost than Dot

2. Good quality

3. 5-10 Sec-A4

4. High Maintenance cost

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Laser

1. High Cost

2. Excellent quality

3. 1-2 Sec-A4

4. Low Maintenance cost

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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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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.

Difference Between Memory & Storage

Memory

VolatileCheepLess Space(2-8GB)Faster

Storage

Non VolatileMore costMore Space(1 TB)Slower than Memory

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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

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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

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Track

Sector

Cluster

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

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Optical Disk Storage

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.

Cross-section of a disk Disk surface magnified

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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 40

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

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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.

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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 43

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

Performance Enhancement for HD

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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 46

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 47

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.