⊕ Hard Disk

 

Faster, expensive, large capacity

 

sealed module, chaper, more convenient.

 

used by all PC's

⊕ Diskette (Floppy Disk)

 

Slower, cheap, small capacity

⊕ Data Organization On Disks

 

Sector Method

 

Data are referred by surface #, track #, and sector number

 

all the vertical tracks ofone cylinder are accessible by the read/write heads wit one positioning of the access arms mechanism.

⊕ Disk Access to Data

 

Seek time

 

Head Switching

 

Rotation Delay

 

Data Transfer

 

Average access time 9ms to 40ms (could be slower)

Web Page Copyright: 國立政治大學資訊科學系 連耀南 lien@cherry.cs.nccu.edu.tw  magdisk.htm,  Sat Feb 5 07:27:05 CST 2011