chapter 7 and 8 input/output and storage · hard drive –storage ram –memory memory vs. storage...

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


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


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: Giving Commands

Keyboard

Mouse

Other Pointing

Devices


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)


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.


Digital CamerasDigital Video

Click on the

picture to play

the video.

Digital Input: Digital Cameras and

Digital Video


Scanners

Flatbed

Fax Machines

Alternative Input Devices

Barcode reader


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


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


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


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

Printer Videos



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.


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


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.


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


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


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


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


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


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


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.

Working of Hard disk



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)


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


chapter 7 and 8 input/output and storage · hard drive –storage ram –memory memory vs. storage...

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