Win 7 Ubuntu 10.04 LTS Dual Boot Fails

Coolname007 said:
What happens when you run these commands at the Grub4Dos prompt:
I tried root (hd0,4) and geometry in the very beginning - that's why I said that grub4dos did not see my Linux partition. I get Error 5 - invalid partition. But Kubuntu live cd and GParted on UBCD see it and mount it just fine. Gujin (from UBCD) even boots it (almost to very end). Since there are already a few recent unresolved threads on this forum about getting into grub4dos prompt instead of Linux - I'd say the problem is with grub4dos rather than my partition.

My system is just 2 year old and completely standard and generic. I used a very popular MSI mobo, all SATA controllers are from the mobo chipset. The system is rock-solid and not even over-clocked.

Those same SCSI IDs stay the same from then on, I believe, regardless of whether one device is disconnected and then reconnected back, or else the computer would get all confused and the boot would probably always fail.
The order is guaranteed only with IDE drives. The order of SATA can easily change, e.g., when hot swapping (or when controllers and their timings are different). The sdX order is how SATA present themselves to the kernel. This could really play havoc with the boot, but that's why grub2 works with uuid in grub.cfg rather than a fixed sdX or hdX order. At least that's my understanding after reading this wiki on Persistent block device naming

So, what could possibly trip grub4dos? ext4? A 2 TB hard drive with the partition at the very end?
 
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So, what could possibly trip grub4dos? ext4? A 2 TB hard drive with the partition at the very end?
Possibly. Honestly, I don't know. You'll have to wait for Computer Guru's (further) input on this issue. But yeah, I'm guessing its because you're trying to boot a logical partition way close to the end of a 2 TB hard drive.
ext4 should be supported already, since that was a problem reportedly fixed a while back for other users using the ext4 filesystem.
 
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By default, when installing onto a free space, Ubuntu creates a logical partition with Ext4 and swap (which, somehow, Win 7 sees as two primary partitions). OK, to test the hypothesis of the problems due to Ubuntu put on a logical partition, I redid everything - this time with a manual installation on primary partitions (one for ext4, one for swap - both created in the free space by installation). So, I got dev/sdb3 and dev/sdb4.

Well, still no cigar, I get into grub4dos prompt. But, there is a difference: now grub4dos at least can see these partitions. Unfortunately, when listed by 'geometry', it shows them as Unknown partitions (83 and 84). Trying to mount ext4 with 'root (hd0,2)' gives Error 15 - 'Unable to mount'.

I think, this confirms that the problem is with grub4dos. And the only reason appears to be a large 2 TB drive. I dearly wish Computer Guru would appear in this thread and take interest in this problem. Maybe there is some special debug version of grub4dos I could use for testing.
 
OK, using exactly the same procedure as before, I installed Kubuntu on a smaller drive, 500 GB (the 3rd drive in the system, so I got dev/sdc2 with ext4 and dev/sdc3 for swap). This time, there was no problem booting into Kubuntu. So, I think it's a positive proof that grub4dos does not support large drives (large being 2 TB).

By the way, in all of the previous attempts, EasyBCD itself recognized the Linux partitions on my 2 TB drive - when selecting legacy grub (just to investigate), they were listed. It was grub4dos that did not.
 
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