Computers: Information Technology in PerspectiveBy Long and Long

Copyright 2002 Prentice Hall, Inc.

Introduction WithIntroduction With Hardware Devices Hardware Devices

Yogesh TomarYogesh TomarYogeshconnect@gmail.comYogeshconnect@gmail.com, ,

98115217829811521782

Copyright 2002 Prentice Hall, Inc.

Computers: Information Technology in PerspectiveBy Long and Long

Copyright 2002 Prentice Hall, Inc.

Storing & Retrieving Storing & Retrieving InformationInformation

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Mass Storage and FilesMass Storage and Files

Programs and information (text, Programs and information (text, image, audio, video) are stored:image, audio, video) are stored: Temporarily in RAMTemporarily in RAM Permanently in Mass Storage (disk Permanently in Mass Storage (disk

and tape)and tape)

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Computer FilesComputer Files

ASCII fileASCII file Data fileData file Document fileDocument file Spreadsheet fileSpreadsheet file Web page fileWeb page file Source program fileSource program file Executable program fileExecutable program file Graphics fileGraphics file Audio fileAudio file Video fileVideo file

.txt.txt

.mdb.mdb

.vdp.vdp

.xls.xls

.htm.htm

.gif.gif.bmp.bmp

.jpg.jpg

.exe.exe

.tif.tif

.wav.wav

.mov.mov

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File Name ConventionsFile Name Conventions

2001 Resume.doc

separated by a periodseparated by a periodseparated by a periodseparated by a period

file extensionfile extension(1 - 3 characters, optional)(1 - 3 characters, optional)

file extensionfile extension(1 - 3 characters, optional)(1 - 3 characters, optional)

filenamefilename(up to 255 chars)(up to 255 chars)

filenamefilename(up to 255 chars)(up to 255 chars)

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What do we do with What do we do with files?files?

Create, name, saveCreate, name, save Copy, move, deleteCopy, move, delete Retrieve, updateRetrieve, update Display, play, printDisplay, play, print ExecuteExecute

Create, name, saveCreate, name, save Copy, move, deleteCopy, move, delete Retrieve, updateRetrieve, update Display, play, printDisplay, play, print ExecuteExecute Download, uploadDownload, upload

Export, importExport, import Compress (zip/unzip)Compress (zip/unzip) ProtectProtect

Download, uploadDownload, upload Export, importExport, import Compress (zip/unzip)Compress (zip/unzip) ProtectProtect

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Physical Storage ProcessPhysical Storage Process

Storage mediumStorage medium

Storage deviceStorage device

–Sequential and/or Random

–Write/Save

–Read/Open

–Sequential and/or Random

–Write/Save

–Read/Open

Storage processStorage process

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Offline and OnlineOffline and Online

Magnetic DisksMagnetic Disks

Magnetic Disk

Hard/Fixed DisksHard/Fixed DisksOnline onlyOnline only

Interchangeable DisksInterchangeable Disks

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Diskette CareDiskette Care

Do store in protected spot, away from Do store in protected spot, away from sun and magnets sun and magnets

Do remove before turning off computerDo remove before turning off computer Do clean them periodically Do clean them periodically Don’t expose to extreme temperatures Don’t expose to extreme temperatures Don’t touch surfaceDon’t touch surface Don’t remove if drive light is onDon’t remove if drive light is on Don’t force it in/out of the driveDon’t force it in/out of the drive

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Hard DisksHard Disks

Anatomy:Anatomy: Recording surfaceRecording surface Multiple plattersMultiple platters Read/write headRead/write head Access armsAccess arms

Courtesy of Seagate Technology

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Fixed Hard DiskFixed Hard Disk

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Magnetic Disk Magnetic Disk OrganizationOrganization

VFAT: Virtual File VFAT: Virtual File Allocation TableAllocation Table

ScanDisk for lost ScanDisk for lost clustersclusters

DefragmentationDefragmentation

FormattingFormatting

Disk SpeedDisk Speed

Access timeAccess time

Data transfer rateData transfer rate

Disk cachingDisk caching

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Backing Up FilesBacking Up Files

Magnetic Tape used for:Magnetic Tape used for: Backup or protectionBackup or protection

Magnetic Tape used for:Magnetic Tape used for: Backup or protectionBackup or protection

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Computer VirusesComputer Viruses

Via Internet when downloading filesVia Internet when downloading files Via e-mail as attachmentsVia e-mail as attachments Via diskette Via diskette Via computer networksVia computer networks Use anti-viral program for your hard Use anti-viral program for your hard

disks and UPDATE IT oftendisks and UPDATE IT often

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Backing Up FilesBacking Up Files

Backup methods:Backup methods: FullFull SelectiveSelective Modified files onlyModified files only

Other backup options:Other backup options: Server computerServer computer Notebook/desktop PCNotebook/desktop PC CD-R or CD-RWCD-R or CD-RW Interchangeable external hard diskInterchangeable external hard disk

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Backing Up FilesBacking Up Files

Internet and network Internet and network serversservers Must be made Must be made fault-fault-toleranttolerant

Use RAID (Redundant Use RAID (Redundant Array of Independent Array of Independent Disks) for backupDisks) for backup

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Optical Laser DevicesOptical Laser Devices

Spiraling Track

Detector

Pit

Land

Sector

Less sensitive to environment

Less sensitive to environment

Cheaper than magnetic disks

Cheaper than magnetic disks

Large data capacity

Large data capacity

Optical Storage

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Optical Disks: Write-OnlyOptical Disks: Write-Only

CD-ROMCD-ROM Compact Disk: read only memoryCompact Disk: read only memory Cannot be alteredCannot be altered Speeds: 32X, 40X or 75X (spin rate)Speeds: 32X, 40X or 75X (spin rate) JukeboxesJukeboxes Capacity: 650 MBCapacity: 650 MB

DVD-ROMDVD-ROM Capacity: 4.7 GB to 17 GBCapacity: 4.7 GB to 17 GB Backward compatible with CD-ROMBackward compatible with CD-ROM

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Optical Disks: Read/WriteOptical Disks: Read/Write

CD-RCD-R Compact disk-Compact disk-

recordablerecordable

CD-RWCD-RW Compact disk-Compact disk-

rewritable rewritable Will not work with Will not work with

older CD-ROM older CD-ROM drivesdrives

DVD-RDVD-R DVD-RAMDVD-RAM

RewritableRewritable

FMD-ROMFMD-ROM Capacity up to 140 GB Capacity up to 140 GB

and backward and backward compatiblecompatible

Computers: Information Technology in PerspectiveBy Long and Long

Copyright 2002 Prentice Hall, Inc.

The EndThe End