GRUB4DOS on 2TB+ drives

I'm trying to use GRUB4DOS to simply boot a 2TB+ drive which contains Windows. The device is an iMac but the drive itself is fully formated by me.

I've done a little research and it seems that others have this problem and it appears to be a limitation with the current version of GRUB4DOS, is this correct? From my research I've also found out that GRUB version 0.97 had a patch to support GPT partitions, can this not be ported over to GRUB4DOS?

http://bugs.gentoo.o...g.cgi?id=178586

How can I get GRUB4DOS to boot and find my Windows Vista bootmgr? Currently it will give a file not found error and I've tested this with most versions of GRUB4DOS including the latest SVN version.

Edited by Mouse, 01 November 2010 - 04:05 PM.

AFAIK grub4dos has NO GPT support.

You may want to experiment with a "Hybrid" partitioning approach, but cannot say if it will work, or if it will work on your particular setup.

Some reference:
http://www.boot-land...?...11600&st=32
http://www.rodsbooks...isk/hybrid.html


Wonko

So theres no way I can get GRUB4DOS working on a 2TB drive without changing it's MBR? Is there a method in which I could format the drive in a way so GRUB4DOS supports it, even if that means reducing the drive to around 1.5TB which I've heard works fine.

So theres no way I can get GRUB4DOS working on a 2TB drive without changing it's MBR?

NO, AFAIK.
grub4dos is comatible with MBR style of partitioning and it is NOT with GPT.
Using a Hybrid MBR/GPT may be able to have grub4dos working whilst keeping the GPT working EXACTLY as before.

Is there a method in which I could format the drive in a way so GRUB4DOS supports it, even if that means reducing the drive to around 1.5TB which I've heard works fine.

Problem is about partitioning (NOT formatting).
If you use a MBR style partitioning, (i.e. with a limit of single boot partition of 2 Tb) grub4dos should work allright (but of course anything that "requires" GPT won't work).
The problem is about a SINGLE partition bigger than 2 Tb in size, if you divide the 2 Tb in more partitions, you should have no problems, and you can use MBR style allright.


Wonko

I've got Windows 7 installed on my 1.5TB HDD and grub4dos is unable to boot it.

The drive is one big NTFS partition, no other partitions exist. I was planning to install other OS's but I'm stuck while it can't even boot just the one.

My menu is basic enough too.

title Windows 7 (x64)

find --set-root /bootmgr

chainloader /bootmgr



title Command line / Error

pause bootmgr not found.

commandline

Does grub4dos work with large drives bigger than 1 terabyte?

For comparison on my other system thats using just a 1TB drive and the same motherboard and setup it works.

Edited by bitbox, 16 December 2010 - 10:14 PM.

I've got Windows 7 installed on my 1.5TB HDD and grub4dos is unable to boot it.

The drive is one big NTFS partition, no other partitions exist. I was planning to install other OS's but I'm stuck while it can't even boot just the one.

My menu is basic enough too.

title Windows 7 (x64)

find --set-root /bootmgr

chainloader /bootmgr



title Command line / Error

pause bootmgr not found.

commandline

Does grub4dos work with large drives bigger than 1 terabyte?

For comparison on my other system thats using just a 1TB drive and the same motherboard and setup it works.

It should print some error messages, what message did it actually print?

It's just failed to boot, skips to bootmgr not found.

I used geometry (hd0) and it's said

Partition num : 0, active, filesystem type is unknown, patition type 0x07

I done some research and apparently it's either a bug or grub limitation. To confirm this I formatted the drive and created a small 100MB NTFS partition at the start and a second larger NTFS partition, this time the geometry looks like this

Partition num : 0, active, filesystem type is ntfs, patition type 0x07
Partition num : 1, filesystem type is unknown, patition type 0x07

grub is able to boot Windows 7 so I tried something else just to confirm things. Create 2 partitions, one with Windows 7 at exactly 1TB at the start of the HDD and the other containing the BCD and bootmgr with the remaining space.

Partition num : 0, filesystem type is ntfs, patition type 0x07
Partition num : 1, active, filesystem type is unknown, patition type 0x07

grub was unable to boot Windows 7.

So is this a bug since it'd seem if the boot files are either on a partition larger than 1TB or are placed after another very large partition then the file system becomes unknown.

Edited by bitbox, 19 December 2010 - 04:39 PM.

with tinybit's 2010-12-19 build and my 1TB WD10EARS drive (single whole partition, aligned) works fine here. for >1TB drive, I need to wait until Tue/Wed to get back my Hitachi 2TB drive for testing.

tested on QEMU with 2000G vmdk harddisk image. (single whole partition formatted with Paragon Partition Manager 9 for DOS)
and it seems fine with tinybit's 2010-12-19 build.

Edited by roytam1, 20 December 2010 - 07:45 AM.

Maybe it's fixed as there were changes recently wasn't there, something to do with the geometry. Then again maybe it's only 1.5TB HDD's that are effected.

I will test a newer build soon but in case you'd like to test I was using this build as it's what I have running on my other system.

http://code.google.c...-11-24-fix2.zip

Also when testing maybe you could mark that partition as active too just to see if that makes any difference.

Edited by bitbox, 20 December 2010 - 04:23 PM.