Re: dd failure odd sectors, block addressing of 1024 question

From: Daniel Phillips (
Date: Fri Jan 04 2002 - 02:28:09 EST

On January 4, 2002 07:45 am, Andreas Dilger wrote:
> On Jan 03, 2002 21:46 -0800, farmer dude wrote:
> > I have a question regarding the use gnufileutils 'dd'
> > wherein it fails to image completely in certain
> > circumstances. I've tossed this around a bit, and so
> > far the best answer seems to be not a DD problem, but
> > rather block addressing within the kernel itself
> > (currently it is 1024bytes???). Someone has suggested
> > I post to this list to see a) if this is a known issue
> > and/or b) what is being done to correct it (say,
> > changing to 512bytes for example)?
> Yes, this is a long standing and well known issue with Linux. As you
> mention later in your email, this does not affect Linux directly, because
> it never uses the last sector of odd-sized disks or partitions. The only
> place it has been noticed is with the Linux NTFS driver (which is unable
> to store the MFT backup in the last sector of the partition) and the NT
> LDM driver which breaks when odd-sized volumes are concatenated together
> (one sector is missing out of the middle of the volume).
> [...]
> In the end, this has been discussed several times on l-k, and while
> people have expressed a desire to fix it, it has never been done.
> This is probably because anyone who knows enough about Linux to fix
> it uses Linux all the time, and at that point they don't need to fix
> it anymore...

It's definitely on the radar.

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This archive was generated by hypermail 2b29 : Mon Jan 07 2002 - 21:00:23 EST