Disk errors when copying

[Ted Mittelstaedt]

geometry is meaningless in LBA mode.

The drive and BIOS mfgr agree on a convenient fiction to
reduce support calls.

Don't forget that running under FreeDOS your running in
real mode not protected mode.  In real mode the segmented
BIOS functions are actually used and it could be they are
even used for addressing the disk, and the disk controller
chipset emulates a MFM controller.  (esentially)

In the protected mode UNIX runs in, most of that BIOS code
is useless, the disk driver talks directly to the disk
controller chipset.  There is probably some undocumented
misbehavior that Microsoft got told about and so put it in
their disk driver code, but that the FreeBSD developers didn't
get told about.

Ted

> -----Original Message-----
> From: Lars Eighner [mailto:luvbeastie at larseighner.com]
> Sent: Monday, September 10, 2007 2:30 AM
> To: Ted Mittelstaedt
> Cc: freebsd-questions at freebsd.org
> Subject: RE: Disk errors when copying
>
>
> On Sun, 9 Sep 2007, Ted Mittelstaedt wrote:
>
> >> From: Lars Eighner [mailto:luvbeastie at larseighner.com]
>
> >> I wish I'd known that before I trashed my disc and spent a
> couple of weeks
> >> and hundreds of bucks building a new system.
> >>
> >
> > One of the rules of thumb when you have hardware problems with a new
> > system (I'm assuming of course that these UDMA errors have been
> > happening since the system was built) is to search both the FreeBSD
> > questions mailing list archives, and the PR database - both closed and
> > open PRs.  Particularly closed PRs are a wealth of information because
> > so many of them are closed for lack of followup.
>
> I got the (disc) manufacture's utilities (which run on a bootable
> FreeDOS CD) and ran every test over and over.  It kept telling me
> the disc was fine.  I should have believed.
>
> I always feel a little weird about discs because although the manufacture
> and the BIOS agree on the geometry, FreeBSD always (over three or
> four boxes
> with a half-dozen different discs) tells me the geometry is
> wrong.  It seems
> so confident about it, I generally let it do what it wants.  But what does
> FreeBSD know about the disc that the manufacture and the BIOS don't?
>
>
> --
> Lars Eighner
> http://www.larseighner.com/index.html
> 8800 N IH35 APT 1191 AUSTIN TX 78753-5266
>
>