Re: 2.4.0 ide driver and old disks

From: Rogier Wolff (
Date: Sun May 28 2000 - 03:29:29 EST

Andries Brouwer wrote:
> Consequently, in my opinion your patch
> > + if (sect == 17 || sect == 26)
> > + drive->present = 1;
> goes in the wrong direction.
> [And concerning this patch, my very old docs all say that the
> number of sectors/track is 17. But my old docs know about quite
> some variety - I see 25, 26, 33, 38 at first sight, there may be more.
> So, given only my docs, the choice of 26 seems a bit arbitrary.]

Oh, the old days!

When I upgraded from an MFM disk to an RLL disk, I had to patch
Minix myself to use the new 26 sectors per track instead of the
old 17 sectors per track. (early '88)

To copy over the contents of my harddisk, I had an intermediate kernel
that supported both formats. I then did "dd if=/dev/hda1 of=/dev/hdb1"
to copy over the data from hda (17 sect/track, 9 sect per track
unused) to the new format (same disk, same cylinders, but 26
sectors/track) The first 17 sectors were read from the exact same spot
on the disk as they were written back to. But after that the read would
always be ahead of the write. Powerfail/crash/^C == deadly.


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*-- BitWizard writes Linux device drivers for any device you may have! --*
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