FAT32 partition not visible in Windows on Triple-Boot System

Could you run 'fdisk' from the OS X terminal so we can see
how the MBR partition table looks?

Thanks.

 

Run "gptsync" from rEFIt. My guess is that the gpt and MBR partitioning schemes are out of sync.

 

Other thing is he probably has 5 partitions: Hidden EFI, OS X, Ubuntu,
Win7, FAT32. That could be an issue given that only 4 primary partitions
are permissible. I'd like to see what's in that partition table

 

I bet that is the core of the issue. The use of FAT32 is also not recommended because any file above 4 GB would stall the use of the partition.

 

Ok, that's great. As you can see, the MBR entries are seemingly correct,
but your storage partition isn't one of them. I would guess the entry wasn't
added to the MBR partition table due to the 4 partition limit.

OS X relies upon the GUID partition table which isn't limited to 4 entries and
your storage partition is partition 6 in that table. That explains why the
partition is visible to OS X, but not to operating systems relying upon the
MBR partition table.

I think there probably is, but I'm not entirely certain.

 

I wonder if a more straightforward solution would be to replace the
EFI entry in the MBR table with a reference to the storage partition.

 

Did you ever solve your problem?

Just started looking into this, as I'm about to implement the same sort of thing. (Triple-boot Mac w/ shared data partition.) I've found lots of contradictory articles on the web. But as best I can tell, it sounds like Windows 7 might not look past the MBR when both an MBR and GPT table are present. If that's true, it would mean your shared data partition would have to be among the first four.

I don't think you want to move Ubuntu out of the first four. I'm assuming Grub is on your Ubuntu partition, and it sounds like Grub might not work if it's on a Mac partition above 4. And you probably don't want to get rid of that first EFI partition. I'm forgetting why, but I recall hearing it was important for some reason.

So you may have to move MacOS out of the first four, to make room for the EFI partition, Linux w/ Grub, Windows, and data. I'm not crazy about this solution. I was under the impression that earlier partitions are toward the outer rim of the drive, leading to faster seek times. So I really wanted MacOS to be my second partition, rather than my fifth. But it looks like I may have to bite the bullet and put the MacOS partition fifth. Let me know if you come up with a better solution, though.

And please correct me if I've got anything wrong.

 

hi guys,

i got it working after countless trial and error formats because the online information is so sketch.

i found partitioning this way works

Initial setup for win7/vista:
1. HFS+ (OSX)
2. FAT32 (Data/Storage/Shared)
3. FAT32/NTFS (Windows 7 or Vista)
4. FAT32 (Linux)

this will make your MBR look like:
1. EFI Protective
2. HFS+
3. FAT32
4. FAT32

and your gpt look like
1. EFI Protective
2. HFS+
3. Microsoft Basic Data
4. Microsoft Basic Data
5. Microsoft Basic Data


then install (in this order) OSX to the OSX Drive, Windows to the Windows drive, and Linux to the linux drive *with the bootloader on the data drive*

====

i would also suggest NOT formatting at all in windows as it will kill your tables.

install ntfs-3g on linux and osx to get ntfs read/write.

 

installing bootloader on data partition is key!

OMG! you really rock - this one tip alone allowed me to get my triple-boot up and running just now - i really thought I had to wipe my drive clean after 12 hrs of work and nope - this tip works!

FYI - this is what worked for me (Mac OS X 10.6.6, WinXP, Ubuntu 10.4):

very happy - i can go to sleep

Code:

Current GPT partition table:
#	 Start LBA	End LBA		Type
1	40	 	409639		EFI System (FAT)
2	409640		 274199287	Mac OS X HFS+
3	 274371432	1128361775	Mac OS X HFS+
4	1128624128	1206747135	Basic Data
5	1206747136	1246746623	Basic Data
6	1246746624	1250263039	Linux Swap

Current MBR Partition Table
# A	Start LBA	End LBA		Type
1	         1	409639		EE EFI Protective
2	    409640	274199287	AF Mac OS X HFS+
3 	 274371432	1128361775	AF Mac OS X HFS+
4 *	1128624128	1206747135	07 NTFS/HPFS

 

sorry to bump this thread... but im in the same boat and need some help!

so about this partition to be shared between 3 oses, how do you format it to be ntfs?

do you do it under mac or ubuntu? and which format should be set?


and what does it mean by setting the bootloader to the data drive? do you set it to point to the shared partition? (if i understand it correctly)

 

wow - it's been so long since I've fiddled with this I hope you others can chime in too...

if I remember correctly, I let my WinXP install do the formatting of my Windows partition.

I did it at the commend level and I think it was from Ubuntu. as long as your partition table looks like the post above, you should be good...

this I'm a bit foggy on as well - if I remember correctly, the "*" on sector 1128624128 denotes where the bootloader is and as you can see in the GPT partition table, it coincides with where I have my DATA (or technically - MEDIA) partition.

I don't think i can help much beyond this so good luck!

 

So does this mean Linux is outside of the MBR and 5th on the GPT?

 

Bump