Secrets of BIOS, Grub, and Triple Boot Servers

Have you read: Rodger’s Very Simple Dual Boot Method?

If you haven’t already, do check it out. One advantage: no Master Boot Record (MBR) modifications! Another advantage: it allows all disks and operating systems the option to be completely independent of each other. You can remove any disk, insert it into another machine, and it will boot perfectly fine. The disks are no longer married to each other. But mainly, this post won’t make any sense to you, otherwise.

A few months ago, I used this method with only two operating systems: Redhat 5.5 and Windows 7. Then recently, in the same server, I installed Redhat 6.4 onto a third disk. But suddenly I had an awful time getting all three to work.

Symptoms:

Redhat 6.4 booted Redhat 5.5 perfectly. But when I booted Windows from the Redhat 6.4 grub.conf file, I got the error:

File:  \BOOT\BCD
Status:  0xc0000001
Info:  An error occurred while attempting to read the boot configuration file

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Redhat 5.5 booted Windows 7 perfectly. But when I tried to boot Redhat 6.4 from the Redhat 5.5 grub.conf file, I got the error:

Error 2: Bad file or directory type

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So, I could only boot two of the three operating systems at one time.  To make things work, I’d have to be changing sata cables. That really defeated the purpose of a triple boot.

This was really mysterious, and no one on the newsgroups had any idea how to fix it. Mere mortals would have given up and implemented some kind of work around. 🙂 But here is how I ultimately overcome the errors and got all the three disks to boot cleanly. 

Rodger’s Very Simple Dual Boot Method

Yesterday, I blogged how to add a Windows hard disk to a Linux installation. I noted, it’s relatively easy to add a Linux disk to a Windows installation, and how the Windows MBR gets overwritten by Linux. But it’s harder to add a Windows disk to an existing Linux installation. The whole process with Supergrub was rather complex, and required many slow reboots.

After thinking about it, a much simpler and effective method came to me. And it works!

In a sentence, the trick is to just modify the boot order in the BIOS, and add the Windows disk to grub.conf. Here’s how to do it.