Re: Cylinder limits jumper for drives over 32GB

From: Andre Hedrick (andre@linux-ide.org)
Date: Sun Mar 26 2000 - 18:30:44 EST


You have to have something returned from the kernel to even attempt a WAG
on geometry........Since we do this in the kernel, why should the resolts
not be exported to USER-SPACE? This way ALL user-space utilities are
using what the kernel declares...........

If you refer to your 20GB reporting "16383/16/63" that is correct.....
Go read the docs on http://www.t13.org/

On Mon, 27 Mar 2000, Daniel J Blueman wrote:

> Hi!
>
> > > (I wonder whether this is a bug. The way I read the ATA-5 spec
> > > it should be possible to do SET_MAX_ADDRESS to the address
> > > gotten back from READ_NATIVE_MAX_ADDRESS.)
> > > A side effect of SET_MAX_ADDRESS is that the current geometry
> > > is reset to 16383/16/63.
> > I gather that it is an LBA exclusive, but I will have to ask.
> > Remember that these calls are primarily workarounds for MS....
> > MS requires LBA..........
>
> It would be absolutely magic if all the cylinder, head and sector geometry
> stuff could be ultimately removed all together. I see problems in hdparm
> reporting ridiculous disk geometry on my 20GB disk.
>
> I think this is a legacy which unfortunately still lives on. As far as the
> kernel goes, it could simply export only the size of disks in terms of the
> number of sectors on the disk (and the sector size), ie LBA information
> (breaking some user-land tools).
>
> Would the only reason to have CHS information exported to user-land be for
> tools such as [c]fdisk doing cylinder-alignment on partitions for
> compatibility purposes? (even if the BIOS and/or drives do not support LBA
> addressing, the kernel could just report LBA information)
>
> Is this the current situation, or am I missing something?
>
> - Dan
> __________________________
> Daniel J Blueman
> Undergraduate - BSc Computing Science
> UMIST university - Manchester
> Direct line: 0161 933 3569
> Mobile: 07775 583766
> Email: daniel.j.blueman@stud.umist.ac.uk
> SMS: daniel.j.blueman@sms.genie.co.uk
>

Andre Hedrick
The Linux ATA/IDE guy

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