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View Full Version : OT: FAT32 Drives, WinXP



chiphart
2005-08-08, 19:08
This is slightly off-topic, but I know someone here will be
familiar with this problem due to the nature of our music
collections.

I have an external 200GB USB drive, formatted by my Linux box
to run FAT32 (one partition). I can pop it any number of other
Linux boxes, OSX machines, even my Win98 machine. However,
when I plug it into an XP machine, I get told that the drive
isn't formatted and do I want to format it now?

Knowing full well that XP won't allow me to format FAT32
partitions > 32GB (in an effort to force NTFS on us), I don't
want to reformat it under XP and recopy everything to it again...
in 32GB partitions. This drive needs to be read by Fedora, OSX,
and XP - what to do?

I presume there are plenty of XP users here with external drives
- anyone seen this? Any advice? I've googled galore with no
luck. Feel free to respond off-line.

Thank you.
--
Chip Hart - Marketing * Physician's Computer Company
chip @ pcc.com * 1 Main St. #7, Winooski, VT 05404
800-722-7708 * http://www.pcc.com/~chip
f.802-846-8178 * Pediatric Software Just Got Smarter.
Your Practice Just Got Healthier.

MrC
2005-08-08, 19:53
I've seen this even with FAT32 floppies formatted in Linux, where they are unreadable in WinXP. Formatted in XP, they work fine back and forth. This leads to the conclusion that there is a slight difference in the partition table, but I've not investigate what the exact differences are.

You can format / clean up the partition table using utilities such as Partition Magic on XP - they will format large (ie. >32G) partitions on XP (its XPs fdisk that is artificially limited).

chiphart
2005-08-09, 06:54
> You can format / clean up the partition table using utilities such as
> Partition Magic on XP - they will format large (ie. >32G) partitions on
> XP (its XPs fdisk that is artificially limited).

First, thank you for the info. Your instinct matches my conclusion.

However, do you think it's possible to "clean up" the partition
table on the drive without removing the data? I've got an old
copy of PM here somewhere, but I'd never used it. I think I'll
try the stuff at http://www.sysresccd.org.

Thanks!

MrC
2005-08-09, 09:01
Yes, PM can write the partition table w/out affecting the partition data. I hedged on the "fix" of the partition map - my thinking was that when PM wrote out the partition table, it might overwrite the info that's causing XP trouble. I can't say with certain recollection, but I believe I've done exactly this in the past.

PM and other utilities can do all sorts of things to the partition table, so your goal would be to change some unimportant aspect (label, type), write out the table, change back and write the table yet again.

Not knowing how old is "old", i'd suggest using sysreccd instead or your old PM. Earlier PMs were not XP compatible w/out patches.

MrC
2005-08-09, 13:25
I gave this some more thought, and it occured to me that the linux-based gpartd is unlikely to resolve the XP problem, in that it probably uses the same code and/or partition header files used by the rest of the system. I'm just guessing here. It would be interesting to hear of your findings.

chiphart
2005-08-18, 06:24
MrC wrote:
> I gave this some more thought, and it occured to me that the linux-based
> gpartd is unlikely to resolve the XP problem, in that it probably uses
> the same code and/or partition header files used by the rest of the
> system. I'm just guessing here. It would be interesting to hear of
> your findings.

...finally grabbed the drive in question and figured it out.
Very simple, very stupid.

When I formatted the drive originally, it looks like I
forgot(?) to partition it. I didn't realize it, but mksys.vfat
will apparently gladly format ol' /dev/sda without a partition.
Linux and OSX will then read the drive, but XP needs partition
info.

Once partitioned (30 seconds with fdisk) and reformatted, I was
all set.

Thanks for the help. Perhaps this will help some other external
drive user.

--
Chip Hart - Marketing * Physician's Computer Company
chip @ pcc.com * 1 Main St. #7, Winooski, VT 05404
800-722-7708 * http://www.pcc.com/~chip
f.802-846-8178 * Pediatric Software Just Got Smarter.
Your Practice Just Got Healthier.

abdomen
2005-08-18, 08:44
I've seen this even with FAT32 floppies formatted in Linux, where they are unreadable in WinXP. Formatted in XP, they work fine back and forth. This leads to the conclusion that there is a slight difference in the partition table, but I've not investigate what the exact differences are.
Windows XP always formats floppies using FAT12. It was my understanding that all operating systems do the same because of the physical design of floppies, but I am not certain of that.

MrC
2005-08-18, 08:50
Windows XP always formats floppies using FAT12. It was my understanding that all operating systems do the same because of the physical design of floppies, but I am not certain of that.

This is incorrect. Floppies can be formated with most any filesystem type, such as HFS, NTFS, Fat16, Fat32, UFS, XFS, raw data, etc.

abdomen
2005-08-18, 09:40
This is incorrect. Floppies can be formated with most any filesystem type, such as HFS, NTFS, Fat16, Fat32, UFS, XFS, raw data, etc.
I stand corrected. I will stick by "Windows XP always formats floppies using FAT12" (until again corrected by someone more knowledgeable).