What does "ckkdsk /R" really do?

  • Thread starter Thread starter Steve Behman
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Steve Behman

Every hard disk has "spare sectors" built in by the manufacturer. These
sectors do not appear in the LBA address space for the disk drive -- they are
reassigned to "bad sectors" and assume the bad sector's LBA when addressed by
the operating system.

My question is:

Does ckkdsk /R cause the hardware reassignment to a "good" hardware spare
sector that will, after the reassignment, be seen as the old LBA or does the
operating system assign the sector to a different LBA (unknown to the
hardware)?

If the hardware reassigns the LBA to a different physical sector then the
hard disk is usable for installing a new operating system. If the sector is
not reassigned a new installation will encounter the same bad sector in the
fullness of time.

I would really appreciate guidance on this issue.
 
Steve said:
Every hard disk has "spare sectors" built in by the manufacturer. These
sectors do not appear in the LBA address space for the disk drive -- they are
reassigned to "bad sectors" and assume the bad sector's LBA when addressed by
the operating system.

My question is:

Does ckkdsk /R cause the hardware reassignment to a "good" hardware spare
sector that will, after the reassignment, be seen as the old LBA or does the
operating system assign the sector to a different LBA (unknown to the
hardware)?

If the hardware reassigns the LBA to a different physical sector then the
hard disk is usable for installing a new operating system. If the sector is
not reassigned a new installation will encounter the same bad sector in the
fullness of time.

I would really appreciate guidance on this issue.
Click to expand...

It can be expected to do what you want, however it will depend more on
what the drive allows than on what CHKDSK can do!
 
Steve said:
Every hard disk has "spare sectors" built in by the manufacturer. These
sectors do not appear in the LBA address space for the disk drive -- they are
reassigned to "bad sectors" and assume the bad sector's LBA when addressed by
the operating system.

My question is:

Does ckkdsk /R cause the hardware reassignment to a "good" hardware spare
sector that will, after the reassignment, be seen as the old LBA or does the
operating system assign the sector to a different LBA (unknown to the
hardware)?

If the hardware reassigns the LBA to a different physical sector then the
hard disk is usable for installing a new operating system. If the sector is
not reassigned a new installation will encounter the same bad sector in the
fullness of time.

I would really appreciate guidance on this issue.
Click to expand...

Chkdsk does not perform sector sparing, it uses a 'software' technique
called cluster remapping, it records the bad sectors in the bad sector
table ($Badclus on NTFS) and remaps the cluster. Sector sparing is a
hardware technique used by the FtDisk driver on fault tolerant SCSI
disks only.

This doesn't matter all that much if you decide to install a new
operating system on the drive as you will (should) perform a full format
when you install the operating system. You should also note that if
chkdsk reports bad sectors it usually means that the spare sector pool
is depleted and the disk should be replaced as sector failure is
somewhat like a snowball rolling downhill, as soon as a few bad sectors
are found other sectors usually start failing in ever increasing numbers
at an ever increasing speed.

John
 
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