0

From microsoft documentation of chkdsk command, it has the following commonly used switches:

/f
Fixes errors on the disk. The disk must be locked. If chkdsk cannot lock the drive, a message appears that asks you if you want to check the drive the next time you restart the computer.

/r
Locates bad sectors and recovers readable information. The disk must be locked. /r includes the functionality of /f, with the additional analysis of physical disk errors.

/b
NTFS only: Clears the list of bad clusters on the volume and rescans all allocated and free clusters for errors. /b includes the functionality of /r. Use this parameter after imaging a volume to a new hard disk drive.


Q1:
Does it mean /r switch will scan for both logical errors in files (logical file corruptions) and physical HDD damages (like bad sectors)?


Q2:
If /r switch does scan for bad sectors, will it scan the entire HDD (both used and free areas) ?


Q3:
Do the differences between /r and /b lie in that /r will skip scanning for the sectors previously marked as bad sectors while /b will scan all sectors (no matter normal or bad)?

Therefore, /b will update the list of marked bad sectors, which means releasing false-positive bad sectors for normal usage (This often happens when cloning an old HDD with bad sectors to a brand new HDD which should have no bad sectors in ideal case). Am I correct?


Q4:
If my understanding is correct in Q3, then I would wonder about the mechanism of determination for bad sectors.

Suppose there is a bad sector(already marked as bad) in old HDD and it is not 100% dead practically, so it could read once in several attempts. Then I clone the old HDD to a brand new one, so the bad sector records are also copied to the new HDD.

If now I run chkdsk /b for the brand new HDD, will there be a chance that this abnormal sector will be released as a normal sector for read/write? That sounds dangerous and unreliable.

Is it worth to use /b for the brand new HDD after cloned?

Improve this question
4
  • Yes for all 4 questions. That sounds dangerous and unreliable. Why? bad sector in old HDD and it is not 100% dead, so it could read once in several attempts After first failed (write/verify or chkdsk /r) attempt it must be marked as bad and it will never be used in future until format, chkdsk /b or similar action.
    – Akina
    Commented Feb 21, 2019 at 11:15
  • @Moab Will /b also scan the entire disk surface?
    – Grace
    Commented Feb 22, 2019 at 7:56
  • According to your research, yes.
    – Moab
    Commented Feb 22, 2019 at 13:25
  • @Akina Thanks for your quick response and clear explanation, would you like to paste your explanation as answer, so I can mark it as answer. Thanks.
    – Grace
    Commented Feb 23, 2019 at 4:09

1 Answer 1

Reset to default
1

Firstly credit to Akinaand Moab

Answers for all 4 questions are yes.

Furthermore, /b switch will scan the entire disk surface.
And after first failed attempt (write/verify or chkdsk /r), the bad sector must be marked as bad and it will never be used in future until format, chkdsk /b or similar action.

Improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .