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* Disk Geometries reported incorrectly on 2.6.0-testX
@ 2003-11-28  4:58 Apurva Mehta
  2003-11-28 14:24 ` Andries Brouwer
  0 siblings, 1 reply; 49+ messages in thread
From: Apurva Mehta @ 2003-11-28  4:58 UTC (permalink / raw)
  To: Linux Kernel Mailing List

Hi,

On 2.6.0-testx kernels, I have noticed that there are problems with
GNU Parted. Parted says that the disk geometries reported by the
kernel are incorrect. Here is a sample error message :

---
Error: The partition table on /dev/hdb is inconsistent.  There are
many reasons why this might be the case.  However, the most likely
reason is that Linux detected the BIOS geometry for /dev/hdb
incorrectly.  GNU Parted suspects the real geometry should be
782/128/63 (not 6256/16/63).  You should check with your BIOS first,
as this may not be correct.  You can inform Linux by adding the
parameter hdb=782,128,63 to the command line.  See the LILO or GRUB
documentation for more information.  If you think Parted's suggested
geometry is correct, you may select Ignore to continue (and fix Linux
later).  Otherwise, select Cancel (and fix Linux and/or the BIOS now).
---

Please let me know if you'll need any additional information.

I am not subscribed to this list so please cc me any replies.

Regards,

	- Apurva

^ permalink raw reply	[flat|nested] 49+ messages in thread
[parent not found: <200311300220.hAU2K0dr019280@sunrise.pg.gda.pl>]
* Re: Disk Geometries reported incorrectly on 2.6.0-testX
@ 2003-11-30  7:08 Norman Diamond
  0 siblings, 0 replies; 49+ messages in thread
From: Norman Diamond @ 2003-11-30  7:08 UTC (permalink / raw)
  To: Andrzej Krzysztofowicz, linux-kernel

Andrzej Krzysztofowicz replied to someone:

> > The BIOS reads the MBR and jumps to the code loaded from there.
>
> I found some PC BIOS-es refuse to read the MBR if no active partition is
> found in the partition table...

They read the MBR but refuse the execute the code contained in it.  Reading
the MBR is the only way that they get to find out that the partition table
includes zero or two (or more) active partitions and decide not to boot.

SuSE 8.1 had this problem.  If you installed grub to a /boot partition but
intended to continue using your existing active partition, the installer
activated the /boot partition.  On the next boot, the BIOS detected two
active partitions and refused to boot from the hard disk.

Booting a floppy still works on most machines.  The BIOS still reads the MBR
and presents the partition table in a block of information that is visible
to the program that gets booted from the floppy disk.  In my experience, the
only machines that refused to do this (becoming 100% unbootable) were the
old NEC 98 architecture.


^ permalink raw reply	[flat|nested] 49+ messages in thread
* Re: Disk Geometries reported incorrectly on 2.6.0-testX
@ 2003-11-30  7:08 Norman Diamond
  2003-11-30 12:49 ` Andries Brouwer
  0 siblings, 1 reply; 49+ messages in thread
From: Norman Diamond @ 2003-11-30  7:08 UTC (permalink / raw)
  To: Andries Brouwer, Andrew Clausen, linux-kernel

Andries Brouwer replied to Andrew Clausen:

> I am happy with that description.
> "Disk geometry is: some numbers that your BIOS invents".

I'm happy with that too.  Now, since the Linux kernel has no fantasies about
disk geometry, it is fine to refuse to provide such non-existent fantasies
to user space.  However, it remains necessary to provide the BIOS's
fantasies to user space.  Sometimes user space does something (via the
kernel) that will later be interpreted by the BIOS.  User space has to be
able to do it in the manner that the BIOS wants.

> > (i.e. have you got any evidence that, say, that 99.x% of Windows XP
> > installations use LBA to bootstrap?)
>
> Just ask yourself this question: does Windows XP require a bootable
> partition to start below the 1024 cylinder mark?
> Windows NT4 has such a restriction. Not Windows 2000 or XP.

The answer is still yes.  Not on sufficiently modern BIOSes but yes in the
way that the booter uses the BIOS to load the kernel.  I think that a
computer dating from 1998 is not terribly old to expect Linux to run,
especially when Linux does run and Windows XP does run.  I have to keep the
following partitions under the 8 GB mark:
C:  (NTLDR, NTDETECT.COM, BOOT.INI, BOOTSECT.LNX, etc.)
D: (WINNT\whatever the names are for kernel, drivers, etc.)
/boot (grub files and vmlinuz-whatever versions)

Windows NT4 SP4 partly overcame the 8GB mark, but of course SP4 was so badly
broken that it is fortunate that the relevant ATAPI.SYS file is downloadable
separately.  This ATAPI.SYS (when renamed to C:\NTBOOTDD.SYS) can load a
kernel for NT4, 2000, or XP even past the 8GB mark, but this file itself and
NTLDR and BOOT.INI etc. must remain below the 8GB mark.  To do this you have
to keep all of C: below the 8GB mark.  If you install Windows 2000 or XP on
such a machine then you have to take a separate download of this specific
version of ATAPI.SYS again, and you have to manually hack BOOT.INI partway
through the installation sequence.  If you don't do things right then
Windows 2000 or XP becomes unbootable, sometimes during the installation
process (if lucky), sometimes years after the install (when a file needed
during booting gets updated and moved).

Anyway, regardless of which OS you're running, the OS isn't running until
it's running.  The MBR depends on BIOS functions (e.g. the infamous INT13)
to read in the boot loader and the boot loader depends on BIOS functions to
read in the kernel.  Yes Dr. Brouwer, I know you know this.  The question is
why you think that commands such as parted don't have to know this?


^ permalink raw reply	[flat|nested] 49+ messages in thread

end of thread, other threads:[~2003-12-03 23:58 UTC | newest]

Thread overview: 49+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2003-11-28  4:58 Disk Geometries reported incorrectly on 2.6.0-testX Apurva Mehta
2003-11-28 14:24 ` Andries Brouwer
2003-11-29  2:22   ` Andrew Clausen
2003-11-29  5:16     ` Szakacsits Szabolcs
2003-11-29  9:18       ` Sven Luther
2003-11-29 12:41         ` Andries Brouwer
2003-11-30 11:44           ` Szakacsits Szabolcs
2003-11-30 15:19             ` Andries Brouwer
2003-11-29 12:34       ` Andries Brouwer
2003-11-29 13:50         ` John Bradford
2003-11-29 14:04           ` Stefan Smietanowski
2003-11-29 17:01           ` Sven Luther
2003-11-29 22:14             ` Andries Brouwer
2003-11-29 22:44               ` Sven Luther
2003-11-30  0:39                 ` Andries Brouwer
2003-11-30  9:35               ` Sergey Vlasov
2003-11-29 22:31           ` Andrew Clausen
2003-11-30  8:57             ` Arjan van de Ven
2003-11-30  7:38               ` Szakacsits Szabolcs
2003-11-30 10:40               ` John Bradford
2003-11-30 11:24                 ` Sven Luther
2003-11-30 13:48                   ` John Bradford
2003-11-30 17:22                     ` Sven Luther
2003-11-30 23:51                 ` Andrew Clausen
2003-11-30 22:54               ` Andrew Clausen
2003-11-29 22:27         ` Andrew Clausen
2003-11-30  0:34           ` Andries Brouwer
2003-11-30 11:10             ` Szakacsits Szabolcs
2003-11-30 13:26               ` Andries Brouwer
2003-11-30 12:34                 ` Szakacsits Szabolcs
2003-11-30 15:46                   ` Andries Brouwer
2003-11-29 22:33       ` Andrew Clausen
2003-11-30  9:16         ` Szakacsits Szabolcs
2003-12-03 11:05           ` Andrew Clausen
2003-12-03 11:28             ` Szakacsits Szabolcs
2003-12-03 11:54               ` Andrew Clausen
2003-12-03 13:07                 ` Szakacsits Szabolcs
2003-12-03 23:27                   ` Andrew Clausen
2003-12-03 21:55                     ` Szakacsits Szabolcs
2003-12-03 23:47                     ` bill davidsen
     [not found] <200311300220.hAU2K0dr019280@sunrise.pg.gda.pl>
2003-11-30  2:22 ` Andrzej Krzysztofowicz
2003-11-30 13:13   ` Andries Brouwer
2003-11-30 13:58     ` John Bradford
2003-11-30  7:08 Norman Diamond
2003-11-30  7:08 Norman Diamond
2003-11-30 12:49 ` Andries Brouwer
2003-12-03 11:06   ` Andrew Clausen
2003-12-03 14:42     ` Andries Brouwer
2003-12-03 23:11       ` Andrew Clausen

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