Fix for the XP dual boot problem

Thu May 20 00:33:04 UTC 2004

Well I was able to fix the problem by simply editing the grub.conf in rescue mode. For some reason it was looking for hd(1,6) instead od hd(0,6). I assume that is because I changed the installetion from hda to hde because I am booting from an sata drive.

Greg

----- Original Message -----
From: Gerry Tool <gstool at earthlink.net>
Date: Wednesday, May 19, 2004 6:19 pm
Subject: Re: Fix for the XP dual boot problem

> Greg Miller wrote:
> > It looks like I may have a similar but different problem.
> > 
> > I wiped FC2test3 and winXP. I then re-installed XP (to solve 
> other problems), then re-installed FC2. It looks like GRUB is 
> screwed up and can not boot linux, but Win XP boots fine. I get an 
> error message that indicates it can't find the partition abd to 
> press a key to continue. The screen is barely readable and I can 
> just select other to go to the XP/dos boot selection.
> > 
> > I'm thinking I need to re-install grub from a rescue boot.
> > 
> > AMD3200
> > K8T800 chipset
> > SATA drive
> > Radeon 9200 Video
> > 
> > Greg.
> > 
> > ----- Original Message -----
> > From: Radu Cornea <ccradu at yahoo.com>
> > Date: Wednesday, May 19, 2004 5:25 pm
> > Subject: Re: Fix for the XP dual boot problem
> > 
> > 
> >>Michal Jaegermann wrote:
> >>
> >>
> >>>The problem is that there is no "wrong geometry".  For quite a 
> while>>>these "geometries" are just inventions and illusions.  Many 
> years>>>ago hard disks indeed had all these head and cylinder 
> geometries,>>>physical ones, but this is a bygone era.  The trouble 
> here is that
> >>>here XP invents one geometry and your kernel another and XP refuses
> >>>to work with what it decided it likes.  Linux kernel is more
> >>>forgiving than that and anaconda should just read what an existing
> >>>partition table said and do not bother with any alerts.
> >>>
> >>
> >>Well, not exactly. What I call "wrong geometry" is when the two 
> >>values 
> >>(physical and logical) don't match. I know the same disk can be 
> >>seen as 
> >>having different geometries (e.g. 16 heads vs 255) but in the 
> >>final 
> >>C*H*S should be the same. As I mentioned in another post I get 
> >>very 
> >>different values from the 2.6 kernel, while 2.4 returns the 
> >>correct ones:
> >>
> >>These are examples from FC2:
> >>$ more /proc/ide/hda/geometry
> >>physical     16383/16/63
> >>logical      19841/16/63
> >>
> >>On another FC2 machine:
> >>$ more /proc/ide/hda/geometry
> >>physical     16383/16/63
> >>logical      16383/255/63
> >>
> >>On a FC1 machine (2.4 kernel) the numbers are ok:
> >>$ more /proc/ide/hda/geometry
> >>physical     155009/16/63
> >>logical      9726/255/63
> >>
> >>The product C*H*S should be the same (or close at least)...
> >>But they are different (even for the same OS, not even talking 
> >>about XP 
> >>here).
> >>
> >>
> >>>Strictly speaking the bug is on an XP side but you are not likely
> >>>fare that well pursuing that.
> >>
> >>I agree this may be fixed on the XP side too. But still the 
> >>installer 
> >>has a problem. Why will it otherwise offer without any warning to 
> >>change 
> >>the mbr, when I did not select any partitioning and I chose to 
> put 
> >>Grub 
> >>in the Linux partition. This reminds me of another OS (guess:)) 
> >>which 
> >>overwrites mbr on install again without asking.
> >>Plus, there are report on bugzilla of people that did run 
> >>partition 
> >>magic after installing FC2 and got a lot of errors (mismatch) in 
> >>the 
> >>partition table.
> >>From the fdisk manual, the mbr stores the info in two ways: as an 
> >>absolute number of sectors and as C/H/S. Windows uses both, while 
> >>Linux 
> >>never uses C/H/S. That's why I think Linux can still boot, and 
> >>Windows 
> >>not. Only C/H/S are changed during installation. That's why it is 
> >>also 
> >>possible to restore the original aprtition table.
> >>Fedora 2 is not the only one affected by it, but also Mandrake 10 
> >>and 
> >>Suse 9.1. See:
> >>
> >>https://qa.mandrakesoft.com/show_bug.cgi?id=7959
> >>http://www.eweek.com/article2/0,1759,1585840,00.asp
> >>
> >>So far this post by Alan Cox seems to be the best explanation why 
> >>this 
> >>problem occurs with 2.6 kernels:
> >>
> >>https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=113201#c13
> >>
> >>"This seems to be a bug in the FC2 tools. The Linux kernel no longer
> >>does partition guessing (its a heuristic and policy at best), as a
> >>result the  parted tools should be honouring existing partition 
> table>>claims when they are present. Failure to do so causes very 
> bad things
> >>to happen.
> >>
> >>Previously these situations the kernel itself would report the
> >>partition table or BIOS guess it made, now its firmly in userspace."
> >>
> >>
> >>--
> >>Radu
> >>
> >>
> >>-- 
> >>fedora-test-list mailing list
> >>fedora-test-list at redhat.com
> >>To unsubscribe: 
> >>http://www.redhat.com/mailman/listinfo/fedora-test-list
> >>
> > 
> > 
> > 
> I had a similar thing happen and discovered with fdisk that the 
> partition it couldn't find was now labled as type 93 (amoeba) 
> instead of 
> 83 (linux).  Check it out.  I was able to correct it with the t 
> command 
> in fdisk.
> 
> Gerry Tool
> 
> 
> -- 
> fedora-test-list mailing list
> fedora-test-list at redhat.com
> To unsubscribe: 
> http://www.redhat.com/mailman/listinfo/fedora-test-list
> 