Andre Hedrick
The Linux IDE guy
On Mon, 13 Sep 1999, Jeff Merkey wrote:
> Andries,
>
> I changed the drive setting to "AUTO" in the CMOS for this drive, and now
> the drive reports 850/63/64. It is interesting to note that there was no
> setting for this disk device that matched any of the configurations you gave
> me. Long ago I wrote an IDE driver on Netware (Wolf Mountain), so I am
> aware of the ability to translate drives into other logical geometries and
> am very famliar with low level IDE stuff (unfortunately). The one thing
> that sucks about IDE and ATA is that both use IO port reads and writes to
> transfer data to and from the disk (which sucks up a lot of bus cycles).
> It's better, however, to get this type of info to the right folks who
> maintain the driver. There are several IDE drivers out there on other OS's
> that for some reason did not implement the new commands for EIDE when they
> came out. I try to focus on the stuff I am supposed to be working on and
> not trying to fix everyone else's bugs, but report then to them instead. I
> did not know if there were underlying hardware issues that I was unaware of
> since it's been about two years since I did any IDE work. I thought someone
> else may be more recently on top of it (like you).
>
> Thanks for the help. I am relieved to know that the Linux IDE drivers are
> not busted and don''t have any cross platform issues that will cuase
> different OS's to report different geometry.
>
> Thanks,
>
> Jeff
>
> ----- Original Message -----
> From: Guest section DW <dwguest@win.tue.nl>
> To: <dwguest@win.tue.nl>; <jmerkey@timpanogas.com>;
> <linux-kernel@vger.rutgers.edu>
> Sent: Monday, September 13, 1999 4:37 PM
> Subject: Re: IDE Driver in Linux Reports different geometry that Netware
> during Volume and Partition Create, causing loss of user data under Linux
>
>
> > > > With a MAXTOR 81750-A4 disk device, Netware reports that this disk
> > > > has a geometry of 850 cylinders, 64 heads, and 63 sectors per
> track.
> > >
> > > That sounds correct.
> > >
> > > > Under Linux, the same device reports a geometry of 780 cylinders,
> > > > 64 heads, and 63 sectors per track.
> > >
> > > I always repeat the same question: what are the boot messages?
> > > And in case you answer you might as well add the output of
> hdparm -I.
> > > My first conjecture in such cases is user error.
> > > For example, the disk may be entered incorrectly in BIOS/CMOS.
> >
> > From jmerkey@timpanogas.com Mon Sep 13 23:13:41 1999
> >
> > Boot messages report the wrong geometry as well. These newer drives
> use a
> > EIDE command to get the correct geometry and typically, at least in
> modern
> > times, don't rely on the information in CMOS since it can be
> incorrect.
> >
> > Jeff
> >
> > Ah - you are naive. There is no `correct geometry'.
> > But there is a geometry reported by the disk (two geometries, in fact).
> > And there is a correct geometry for doing I/O (if LBA is not used).
> > And there is a correct geometry for booting, for LILO to use.
> > And there is a correct geometry for interaction with other
> > operating systems - the one that everybody agrees upon for the
> > interpretation of the partition table.
> > These geometries differ in general.
> >
> > The disk here reports 3400 cylinders, 16 heads and 63 sectors per track.
> > For the partition table you would have liked 850 cylinders, 64 heads,
> > and 63 sectors per track.
> > It sounds as if you told the computer in the CMOS setup not to use
> > more than 780 cylinders.
> >
> > If that is the case, then just correct that, and the problem is gone.
> > Otherwise I would like to see more precise data.
> >
> > Andries - aeb@cwi.nl
> >
>
>
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