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Copyright ? 2006 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill Technology Education
McGraw-Hill Technology Education Copyright ? 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
Copyright ? 2006 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill Technology Education
Chapter 6B
Measuring and
Improving Drive
Performance
6B-3
Drive Performance
? Average access time
¨C Also known as seek time
¨C Time to find desired data
¨C Measured in milliseconds
¨C Depends on two factors
? RPM
? Time to access a track
¨C Hard drive between 6 and 12 ms
¨C CD between 80 and 800 ms
6B-4
Drive Performance
? Data transfer rate
¨C How fast data can be read
¨C Measured in Bps or bps
¨C Hard drive ranges from 15 to 160 MBps
¨C CD ROMS depend on X factor
? 24x CD transfers 24 x 150 KBps
¨C Floppy disks transfer at 45 KBps
6B-5
Data Transfer Rate
6B-6
Optimizing Performance
? Disk optimization
¨C Handled by operating system tool
¨C Routine disk maintenance
¨C Optimization should be run monthly
6B-7
Optimizing Performance
? Clean up unnecessary files
¨C Delete temp files
¨C Uninstall unused programs
¨C Delete obsolete data files
¨C Files should be cleaned weekly
6B-8
Optimizing Performance
? Scan a disk for errors
¨C Bad spots on the media
¨C Find and fix the error
? Move data to a good spot
? Mark the spot as bad
¨C Disks should be scanned monthly
6B-9
Optimizing Performance
? Defragment a disk
¨C Files fragment when resaved
¨C Fragmented files load slower
¨C Defragment puts the fragments together
¨C Disks should be defragged monthly
6B-10
Defragment
6B-11
Optimizing Performance
? File compression
¨C Shrinks the size of a file
¨C Takes up less space on disk
¨C Reduce a disks performance
¨C Will increase disk capacity
¨C PKZip, WinZip and WinRAR
6B-12
File Compression
763 KB
on disk
Compressed
157 KB
6B-13
Drive Interface Standards
? Interface
¨C How the device is connected
¨C Drive controllers allow transfer of data
¨C Dictates transfer rate and access time
6B-14
Drive Interface Standards
? Enhanced Integrated Drive Electronics
¨C EIDE
¨C Generic term for drive controllers
¨C Several names
? Fast IDE
? Advanced Technology Attachment (ATA)
¨C Up to 2 devices per controller
¨C Most computers have 2 EIDE controllers
6B-15
Drive Interface Standards
? Small Computer System Interface
¨C SCSI
¨C Higher transfer rates than EIDE
¨C More than 40 devices per SCSI controller
? Computers may have several SCSI controllers
¨C Many versions exist
? Versions are typically incompatible
¨C Found in servers and workstations
6B-16
Drive Interface Standards
? USB and FireWire
¨C External drives
¨C Transfer rate is limited
¨C Many devices can be connected
Copyright ? 2006 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill Technology Education
Chapter 6B
End of Chapter

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Intro ch 06_b

  • 1. Copyright ? 2006 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill Technology Education McGraw-Hill Technology Education Copyright ? 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
  • 2. Copyright ? 2006 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill Technology Education Chapter 6B Measuring and Improving Drive Performance
  • 3. 6B-3 Drive Performance ? Average access time ¨C Also known as seek time ¨C Time to find desired data ¨C Measured in milliseconds ¨C Depends on two factors ? RPM ? Time to access a track ¨C Hard drive between 6 and 12 ms ¨C CD between 80 and 800 ms
  • 4. 6B-4 Drive Performance ? Data transfer rate ¨C How fast data can be read ¨C Measured in Bps or bps ¨C Hard drive ranges from 15 to 160 MBps ¨C CD ROMS depend on X factor ? 24x CD transfers 24 x 150 KBps ¨C Floppy disks transfer at 45 KBps
  • 6. 6B-6 Optimizing Performance ? Disk optimization ¨C Handled by operating system tool ¨C Routine disk maintenance ¨C Optimization should be run monthly
  • 7. 6B-7 Optimizing Performance ? Clean up unnecessary files ¨C Delete temp files ¨C Uninstall unused programs ¨C Delete obsolete data files ¨C Files should be cleaned weekly
  • 8. 6B-8 Optimizing Performance ? Scan a disk for errors ¨C Bad spots on the media ¨C Find and fix the error ? Move data to a good spot ? Mark the spot as bad ¨C Disks should be scanned monthly
  • 9. 6B-9 Optimizing Performance ? Defragment a disk ¨C Files fragment when resaved ¨C Fragmented files load slower ¨C Defragment puts the fragments together ¨C Disks should be defragged monthly
  • 11. 6B-11 Optimizing Performance ? File compression ¨C Shrinks the size of a file ¨C Takes up less space on disk ¨C Reduce a disks performance ¨C Will increase disk capacity ¨C PKZip, WinZip and WinRAR
  • 12. 6B-12 File Compression 763 KB on disk Compressed 157 KB
  • 13. 6B-13 Drive Interface Standards ? Interface ¨C How the device is connected ¨C Drive controllers allow transfer of data ¨C Dictates transfer rate and access time
  • 14. 6B-14 Drive Interface Standards ? Enhanced Integrated Drive Electronics ¨C EIDE ¨C Generic term for drive controllers ¨C Several names ? Fast IDE ? Advanced Technology Attachment (ATA) ¨C Up to 2 devices per controller ¨C Most computers have 2 EIDE controllers
  • 15. 6B-15 Drive Interface Standards ? Small Computer System Interface ¨C SCSI ¨C Higher transfer rates than EIDE ¨C More than 40 devices per SCSI controller ? Computers may have several SCSI controllers ¨C Many versions exist ? Versions are typically incompatible ¨C Found in servers and workstations
  • 16. 6B-16 Drive Interface Standards ? USB and FireWire ¨C External drives ¨C Transfer rate is limited ¨C Many devices can be connected
  • 17. Copyright ? 2006 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill Technology Education Chapter 6B End of Chapter