[ILUG-BOM] RH Linux not overwriting MBR.

Rajesh Deo rajeshdeo@[EMAIL-PROTECTED]
Sat Jul 20 08:05:06 IST 2002


On Fri, 2002-07-19 at 02:45, Kunal Gangakhedkar wrote:

> Well, as I could gather from the discussions held earlier on this group, 
> having an old bios & connecting a 40GB hdd should not cause any problems.
> The linux kernel has algorithms to directly talk to the HDD controller - 
> without the intervention of the BIOS. This was a news for me.
> In that case, it really does not matter what the BIOS shows you.
> You still should be able to access all 40gigs thru' linux.

With Linux up and running thats fine, troubles arise only when one is
booting using a older bios and/or older versions of boot loaders like
Lilo,the large disk troubles also arise if different operating system on
the same disk has different understanding of disk geometry. Even if you
use the native partitioning tool in the respective operating system, the
resulting partition structure can be troublesome to other OSes on the 
system. Since most commonly used OSes like Win98 SE, Win NT 4./2000/ XP
and newer versions of Linux know about accessing large disks, using and
partitioning large disks is not a problem any more. As the
Large-Disk-HOWTO says, everything is fine by default, it is only when
you have really ancient hardware/bios and if you force the Linux kernel
to see a particular disk geometry that problems can arise.


> > Windows C: on hda. It has 2 more windows partitions.
> >
> > For hdb the partitions are as follows:
> >
> > hdb1 - Windows
> > hdb2:
> >      hdb5, hdb6.... <10 partitions>. All Windows.
> > hdb3 - Linux native, mount point / - 10Gb
> > hdb4 - Linux swap - 200 Mb
> >
> > It goes through the entire installation process, and asks me to
> > reboot. But then directly boots into Windows. Tried Lilo & Grub. I
> > explicitly asked to overwrite MBR during installation.
> 
> Well, it also depends on which version of Windows you're using.
> If you're using something like ME or XP then, the Windows OS protects the MBR 
> somehow. So, any other software which tries to access / overwrite MBR will 
> fail.

I have two machines running Win XP and Linux running, Win XP does not
protect/overwrite the MBR. Neither does any other version of Windows.

> The solutions - many.

Now we don't need any :-)
 
[snip]

> 2. If you have NT Boot Loader (if using XP), then create an image file of the 
> boot sector using dd. Copy this file to some windows partition. Edit your 
> boot.ini to add an entry corresponding to this new boot sector file.
> That's all. From next time onward, you'll have an entry in your NT boot loader 
> menu which will load the original Linux boot sector.
> The only problem is you'll have to do it everytime you modify your boot 
> sector. I USE THIS METHOD TO BOOT INTO RH 7.3 FROM Win2K BOOT LOADER. 

Gee, Such a lot of trouble, just use lilo or grub to boot Win2k, no need
to do a hell lot of skirmish to use your brand new custom kernel :-)

have fun,

Rajesh





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