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Hotchips 02-07-2007 02:50 AM

trying for dual boot after adding linux to WinXP
 
Hi,

I have just added a linux install to my PC but am not sure hot to tell boot.ini to give me an option for dual boot.

Linux boot partition set up on same disk as Windows boots from. Some other partitions are set up on another disk. I set the RedHat option to dual boot with the grub loader but when I boot up, windows just comes straight up.

Help please?

Cheers,

wahming 02-07-2007 02:54 AM

Did you install Linux first, or Windows? What distribution of linux did you use? Where did you install grub to, the MBR, or the /boot partition?

Hotchips 02-07-2007 03:14 AM

Thanks for prompt response.

Windows has been there for a while.

RHEL ES 4 Update 2.

Not sure where I installed grub - just went through the graphical install screens. When it was time to set grub, the two O/S were listed and I ticked Windows to be default. I cannot recall being asked for a location to install grub.

I have 1 x IDE HDD and 2 x SATA II drives. Windows is on first sata drive - I thought that was where I put /boot but just checked - /boot partition is on disk 0 which is my IDE drive.

I think I'll get more practice and reinstall linux again - this time with /boot on same drive as WinXP is booting from.

Is there more to consider than just installing and going through the wizard?? I have read a few things regarding the boot.ini and the MBR needing adjusting. Is this a must or can I add Linux to my PC without editing these crucial files??

wahming 02-07-2007 03:26 AM

Default install sends grub to mbr. In that case, no editing is required. Windows does grumble about it occasionally, but that's not a big deal. Advanced bootloader options lets you pick MBR or /boot for grub.

If you like, you can try booting into rescue mode with your linux cd. chroot to /mnt/sysimage, then run grub-install /dev/hda (depends on your bios boot order here)

Speaking of bios boot orders - check your bios setup. Which disk are you booting from? (May be different from which disk your Win is on)

pixellany 02-07-2007 07:27 AM

During a normal install, GRUB will be installed to the mbr of the drive that the installer believes is #1 This is not the first time I have read of confusion when mixing IDE and SATA drives.

One way that should work is to simply put Linux on the same drive as Windows (with the BIOS set to boot that drive).

If you install GRUB, then you do not need to be concerned about boot.ini---GRUB takes over the mbr and the stage1 Windows code is replaced.

If you still have problems, you can always put GRUB on a floppy. Then you can put it on the mbr later when you have everything else working.

Hotchips 02-07-2007 07:32 AM

I am not getting any option at boot time to select OS.

I reinstalled RHEL4 - with /boot partition on same HDD as WinXP partition but still not getting a boot option.

If grub has gone to mbr, why do I not get an option to choose?

Shall I post screen grabs of Disk arrangements?? Is the problem bigger than what boots first?

Am I correct to say the master boot record exists on the frst x amount of bytes on the first disk detected at the post stage????

I apologise if these questions are not the right ones to ask. I merely seek knowledge. :)

wahming 02-07-2007 07:36 AM

When you turn on the computer, enter the bios setup. Look for an option that lets you choose which hard disk you're checking first, for bootable partitions. Make sure it's the hd with the dualboot setup installed. I suspect grub installed to the MBR of your first sata drive, but bios is using another hd's MBR to boot.

pixellany 02-07-2007 07:40 AM

Does GRUB appear at all? What is likely happening is that it can't find its config file---which lives at /boot/grub.

The mbr is the first sector (512 bytes) of the drive. 446bytes boot code (eg grub stage1) 64 bytes partition tables, 2 byte signature.

Quote:

Am I correct to say the master boot record exists on the frst x amount of bytes on the first disk detected at the post stage????
Every drive has an mbr--the one that gets used is based on the BIOS settings--it makes no difference whcih drive the POST detects first.

One thing that might lessen the confusion would be to disconnect the IDE drive. Then, with the BIOS set to boot the Windows drive, the installer should clearly see that as #1.

Or install GRUB on a floppy during install

wahming 02-07-2007 07:55 AM

According to the OP grub doesnt get detected, it boots straight to Windows. Doesn't sound like a lost grub.conf

Try pixellany's solution. You might want to try disconnecting the other Sata drive too, since you didn't specify which is master/slave

bigrigdriver 02-07-2007 09:00 AM

If you would rather keep the xp ntldr as the boot loader, search these boards. That topic has been discussed before.

If that fails to turn up favourable results in re booting Linux using the xp bootloader, try the Linux help forum at the Micro$oft support website. They should have instructions on the setup.

pixellany 02-07-2007 09:20 AM

Quote:

Originally Posted by bigrigdriver
If you would rather keep the xp ntldr as the boot loader, search these boards. That topic has been discussed before.

If that fails to turn up favourable results in re booting Linux using the xp bootloader, try the Linux help forum at the Micro$oft support website. They should have instructions on the setup.

Tried looking for this, but could only find linux topics by searching on "linux"

One cute thing: When you search on linux it asks you if you meant to say "uninstall linux"

I don't know whether to be happy that MS has Linux stuff on their site....;

wahming 02-07-2007 09:32 AM

Quote:

Originally Posted by pixellany
One cute thing: When you search on linux it asks you if you meant to say "uninstall linux"

I don't know whether to be happy that MS has Linux stuff on their site....;

Rofl. Talk about subtlety

Hotchips 02-07-2007 09:25 PM

Thanks all. :D :D :D

I changed the order of hard drives in the BIOS as suggested and hey presto!

On a related issue, the grub option only appears for 2 seconds (or so it seems). Where is the setting to increase the time before default OS is loaded?

Also, (sorry for the laziness of not posting new threads) :tisk:

creating a boot floppy....

1. Is a rescue floppy the same as a boot floppy in terms of what is on the disk? ie. Does rescue floppy include things that a regular bootable linux floppy does not? - I just want to clarify if the term 'rescue disk' is simply a boot floppy - or a bit more than that.

2. I have read that I can create a boot disk from the first RedHat CD by copying the bootdisk.img file to a floppy. This is not present on the CD and all the image files are greater than 1.4mb. Is RedHat moving away from creating a bootable floppy?? I want to practice booting from a floppy - with network support if possible so I can install Linux from an nfs server. Something I have done from installation CD successfully:D
How can I create the floppy?? There is a vmlinuz file but I don't know if this creates a boot disk.

Again, thanks for helping with grub.

Oh, and as for Microsoft site pointing to an uninstall... How rude! I would have thought a company as big as that would have some maturity! Personal message to Bill Gates - get over it! embrace linux, it is your friend!

wahming 02-07-2007 10:09 PM

No idea about the floppies.

Would you embrace your competitors when you're trying to maintain a monopoly? =D

Edit the /boot/grub.conf file for the time setting

Hotchips 02-08-2007 12:03 AM

Thanks wahming.


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