Re: Linux 2.6.3-rc3 - IDE DMA errors on Thinkpad A30

Bill Davidsen
2004-02-16T12:25:34Z

Jeff Garzik wrote:
> Valdis.Kletnieks@vt.edu wrote:
>
>> On Sun, 15 Feb 2004 22:47:37 EST, Jeff Garzik said:
>>
>>> One for the todo list, I suppose... a useable workaround for this is
>>> probably good ole 'e2fsck -c', i.e. badblocks... That says "check
>>> again to see if this sector is bad", and -hopefully- will unmark bad
>>> blocks that were incorrectly marked bad.
>>
>>
>>
>> Does e2fsck/badblocks issue the right ioctls/etc to make the disk read
>> the
>> *original* block, or will the disk simply check the *redirected* block?
>
>
>
> I'm not sure your question has meaning.
>
> Consider: ext2 reads sector 1234. drive returns "media error", and
> then swaps the bad sector for a good one. Reboot and run badblocks.
> badblocks reads sector 1234, in whatever manner the drive chooses to
> present sector 1234 to the OS.

That's the point, the original 1234 may not really be bad.
>
> "original" versus "redirected" block is invisible to the OS. The OS
> only knows that an event occured at a single point in time -- the media
> error.

It's invisible unlesss the o/s chooses to see. By default there would
never be an attempt to recheck the original sector 1234 unless the o/s
tells the drive to do so. It may be that a write to the sector will work
and there is nothing wrong with the sector (transient errors could be
caused by mechanical or electrical transients, more likely in a laptop).

--
bill davidsen <davidsen@tmr.com>
CTO TMR Associates, Inc
Doing interesting things with small computers since 1979