Chapter 6B - Measuring and improving drive performance. This chapter define the term average access time and describe how it is measured, explain why file compression is a factor in drive performance, define the term data transfer rote and describe how it is measured, explain two steps you can take to optimize the performance of your computer’s hard disk, identify four drive interface standards commonly used in PCs. | McGraw-Hill Technology Education Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved. Chapter 6B Measuring and Improving Drive Performance Drive Performance Average access time Also known as seek time Time to find desired data Measured in milliseconds Depends on two factors RPM Time to access a track Hard drive between 6 and 12 ms CD between 80 and 800 ms 6B- Teaching tip To provide contrast, present the speed of memory as measured in the nanoseconds, or billionth of a second. Then discuss virtual RAM as defined earlier in the text. More RAM, less virtual RAM makes a faster machine. Drive Performance Data transfer rate How fast data can be read Measured in Bps or bps Hard drive ranges from 15 to 160 MBps CD ROMS depend on X factor 24x CD transfers 24 x 150 KBps Floppy disks transfer at 45 KBps 6B- Insider information Most hard disks do not list the time to access a track. This is a good topic to tread lightly with. Data Transfer Rate 6B- Optimizing Performance Disk optimization Handled by operating system tool Routine disk maintenance Optimization should be run monthly 6B- Optimizing Performance Clean up unnecessary files Delete temp files Uninstall unused programs Delete obsolete data files Files should be cleaned weekly 6B- Teaching tip Figure on page 249 shows the disk cleanup utility for Windows XP. Optimizing Performance Scan a disk for errors Bad spots on the media Find and fix the error Move data to a good spot Mark the spot as bad Disks should be scanned monthly 6B- Optimizing Performance Defragment a disk Files fragment when resaved Fragmented files load slower Defragment puts the fragments together Disks should be defragged monthly 6B- Insider information Windows 9x required the screen saver to be disabled before running scan or defrag. Failing to disable the screen saver could lead to catastrophic data loss! Defragment 6B- Optimizing Performance File compression Shrinks the size of a file Takes up | McGraw-Hill Technology Education Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved. Chapter 6B Measuring and Improving Drive Performance Drive Performance Average access time Also known as seek time Time to find desired data Measured in milliseconds Depends on two factors RPM Time to access a track Hard drive between 6 and 12 ms CD between 80 and 800 ms 6B- Teaching tip To provide contrast, present the speed of memory as measured in the nanoseconds, or billionth of a second. Then discuss virtual RAM as defined earlier in the text. More RAM, less virtual RAM makes a faster machine. Drive Performance Data transfer rate How fast data can be read Measured in Bps or bps Hard drive ranges from 15 to 160 MBps CD ROMS depend on X factor 24x CD transfers 24 x 150 KBps Floppy disks transfer at 45 KBps 6B- Insider information Most hard disks do not list the time to access a track. This is a good topic to tread lightly with. Data Transfer Rate 6B- Optimizing .
