Is the number of sectors fixed for each track in a hard drive? I am wondering about this because most hard drive specifications give an accurate value for sectors/track rate. I am confused because I would imagine the inner tracks should contain less sectors than the outer tracks.


Number of sectors per track
(more sectors on the outside as apposed to the tracks near the spindle,)
ATA/IDE drives were much more efficient at storing data and have replaced the now archaic MFM and RLL drives. They use zone bit recording (ZBR), where the number of sectors dividing each track varies with the location of groups of tracks on the surface of the platter.
Tracks nearer to the edge of the platter contain more blocks of data than tracks close to the spindle,because there is more physical space within a given track near the edge of the platter.
Thus, the CHS addressing scheme cannot correspond directly with the physical geometry of such drives, due to the varying number of sectors per track for different regions on a platter. Because of this, many drives still have a surplus of sectors (less than 1 cylinder in size) at the end of the drive, since the total number of sectors rarely, if ever, ends on a cylinder boundary.
For reff.
See MFM and RLL drives and below ATA/IDE drives:- See History

  • 1
    Cheers to not having to know this any longer. I don't miss the passing of the old CHS swamp where you prayed the BIOS came close. ATA/IDE brought in a welcome change. With the increase in data density during its reign, drive technology started recovering wasted space by moving from having sectors cover the same arc from center to rim and went to zone bit recording which sets up zones where the sectors per track jump to keep them more the same density per sector over the full surface of the drive. Dec 25 '11 at 4:56

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