What happens to bad sectors?

[Bly]

Hi, looking at the manual and forum, I still don't get what happens to bad sectors after they are marked as bad/unrecoverable.

Are they put in a list and and I can forget them, or they will be encountered again if I install any file system on the disk?

I'd like to use a drive I know has failing sectors but not important stuff so I'm fine with it, I just will be happy any bad sector being marked as.. bad! and forget it afterwards, is this possible?

And, running spinrite once every six months or so, is it possible adding the new bad ones without losing time on the sectors previously marked bad I won't want or care to recovery?

TIA!

 

[peterblaise]

As far as I understand, for 'modern' IDE/ATA/AHCI drives:

Sectors marked bad by the operating system, such as via ChkDsk /r, may be returned to try, try, try again after subsequent reformatting or clearing by any method. SpinRite will re-check these. SpinRite 6.1 will NOT 'tell' the operating system. SpinRite 6 will.

Sectors 'marked bad' by SpinRite and by the drive itself, generally are reallocated so they 'appear' as useful LBA logical block addresses once again, the drive appearing flawless, the bad sector physical location never to be used again, the good replacement address to carry on. Since the original bad physical address is 'gone', SpinRite will not recheck the original physical address, only check the reallocated new good address.

If we can see a SpinRite log attached to a post here in the GRC Forums, then we can deduce more.

If the bad sector count grows, the drive may be heading for inoperability.

If the bad sector count stays stable, they may be idiopathic, 'acceptable'.

- - - - -

Hey, gang, have I got it? Is there more?

How involved are the particulars and exceptions?

Is it possible to create an exhaustive chart?

.

 

[DanR]

Hi, looking at the manual and forum, I still don't get what happens to bad sectors after they are marked as bad/unrecoverable.

Are they put in a list and and I can forget them, or they will be encountered again if I install any file system on the disk?

Hi Bly! And welcome to the forum! Good questions!

If SpinRite is in data recovery (Level 2 and up) SR will attempt to write all zeros to a bad sector. This will typically trigger the drive's firmware to "re-allocate" the bad sector by taking it out of service and replacing it with a good sector from good sectors reserved on the drive for that purpose. A re-allocated bad sector will never be seen again by SpinRite, any OS, or any file write.

I'd like to use a drive I know has failing sectors but not important stuff so I'm fine with it, I just will be happy any bad sector being marked as.. bad! and forget it afterwards, is this possible?

Yes. Since data loss is not a concern, a level 2 DynaStat 0 run will typicality force re-allocation of all unreadable sectors: C:\>spinrite dynastat 0 level 2
or C:\>spinrite dynastat 0 and select level 2 in the SpinRite app.

And, running spinrite once every six months or so, is it possible adding the new bad ones without losing time on the sectors previously marked bad

Yes.

I won't want or care to recovery?

This drive should never be used for important or critical data.

 

[ColbyBouma]

If SpinRite is in data recovery (Level 2 and up) SR will attempt to write all zeros to a bad sector.

DynaStat will write whatever it was able to recover. This may be nothing (all zeroes), part of the data, or all of the data.
https://gitlab.com/GRC-Community/spinrite-6.1-wiki/-/wikis/Command-Line#norewrite

 

[DanR]

DynaStat will write whatever it was able to recover. This may be nothing (all zeroes), part of the data, or all of the data.

Ah . . . yes! The subtleties of SpinRite.

 

[Bly]

Thank you all for the informations! I'll do as suggested, level 2 and dynastat disabled.
And, ofc, that drive is for various experiments so no important data