[ILUG-BOM] RH Linux not overwriting MBR.

Kunal Gangakhedkar kgangakhedkar@[EMAIL-PROTECTED]
Fri Jul 19 13:05:06 IST 2002


> Slave: 32 Gb [hdb] (is 40 Gb, but my BIOS treats it as 32 Gb)

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.

> 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.

The solutions - many.

Prerequisite  -  Write the Linux bootloader (any) into the First Boot 
Partition and not in MBR.

1.  Use some other bootloader like XOSL to boot into it. But then, I don't 
know whether the new XOSL supports GRUB, it surely does support Lilo.
It cannot boot into linux without a "regular" linux boot loader.
Check out the linux kernel boot sector documentation for why.

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. 

3. Find out if the Windows protection of MBR can be removed. If yes, then you 
can safely install any linux loader into MBR. But it is kinda risky. You 
cannot guarantee proper booting of windows after that. USE IT AT YOUR OWN 
RISK. After all it is windows.

Kunal Gangakhedkar
(kgangakhedkar at softhome.net)
(kgangakhedkar at hotpop.com)





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