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GRUB4DOS on 2TB+ drives


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#1 Mouse

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Posted 01 November 2010 - 03:42 PM

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.


#2 Wonko the Sane

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Posted 02 November 2010 - 09:21 AM

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

:cheers:
Wonko

#3 Mouse

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Posted 02 November 2010 - 02:33 PM

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.

#4 Wonko the Sane

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Posted 02 November 2010 - 03:06 PM

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.

:cheers:
Wonko

#5 bitbox

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Posted 16 December 2010 - 10:02 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.

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


#6 roytam1

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Posted 19 December 2010 - 02:02 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?

#7 bitbox

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Posted 19 December 2010 - 04:37 PM

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.


#8 roytam1

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Posted 20 December 2010 - 03:11 AM

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.

#9 roytam1

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Posted 20 December 2010 - 07:44 AM

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.
Posted Image

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


#10 bitbox

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Posted 20 December 2010 - 04:16 PM

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.





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