Mounting a possibly corrupt FAT32 partition?

[spiritofcat]

Windows has stopped booting.

I have FC4 and WinXP installed as a dual boot system, with grub configured to default to booting WinXP.
After the countdown, where it would normally start booting windows, it not just displays this:

rootnoverify (hd0,0)
chainloader +1

And does nothing more.

I thought that maybe something had gone wrong with the windows boot files, so I investigated how to read NTFS partitions in FC4.
Thanks to http://linux-ntfs.sourceforge.net/rpm/instructions.html I succeeded, but then discovered that the main windows drive was actually FAT32.

So now what I mant to do is mount the FAT32 partition so that I can recover the data that was stored there.

[root@localhost windows]# /sbin/fdisk -l

Disk /dev/hda: 40.0 GB, 40007761920 bytes
255 heads, 63 sectors/track, 4864 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hda1   *           1        1891    15189426    c  W95 FAT32 (LBA)
/dev/hda2            3589        4863    10241437+   7  HPFS/NTFS
/dev/hda3            4864        4864        8032+   e  W95 FAT16 (LBA)
/dev/hda4            1892        3588    13631152+   5  Extended
/dev/hda5            1892        1904      104391   83  Linux
/dev/hda6            1905        3588    13526698+  8e  Linux LVM

Partition table entries are not in disk order

As you can see, /dev/hda1 is the FAT32 parition that I want to mount.

When I try to mount it using

mount /dev/hda1 /mnt/windows -t vfat -r umask=0222

I get this error:

mount: wrong fs type, bad option, bad superblock on /dev/hda1,
missing codepage or other error
In some cases useful info is found in syslog - try
dmesg | tail  or so

And when I do as it says I find this:

FAT: bogus logical sector size 514
VFS: Can't find a valid FAT filesystem on dev hda1.

So /sbin/fdisk -l is telling me it's FAT, but mount disagrees.
Is it simply the case that the partition is corrupted, or am I doing something wrong?

[tashirosgt]

I don't make dual boot systems myself, but let me bump this thread since you gave a reasonable amount of information.

I see nothing wrong with your commands, but then again, I seldom mount vfat files. Do you have another FAT32 partition or can your create one? Will the command you used mount it ? Can you boot with a Windows boot floppy and see hda1 as C:?

A person who knows the details of FAT32 might be able to tell from inspecting the bytes on the drive if the header is bad (as hinted by http://groups-beta.google.com/group/...63ca36abfdf9a4
When you search with Google, don't forget to try Google Groups !)

That person wouldn't be me today, but the web probably has a page where the FAT32 format is given in detail.

[spiritofcat]

Thanks for the bump.
I'll try making another FAT32 partition and see if I can mount it.

[tashirosgt]

To me it would interesting to examine the partition table byte by byte. The first "block" of bytes on the drive can be displayed with commands like
dd if=/dev/hda of=myjunk.txt count=1
od -tu1 myjunk.txt | less
This is dangerous unless you know what you are doing ... and I don't quite. You'll have to see how adventurous you feel. Perhaps we could find the location of the 514 that the error message complains about.

[spiritofcat]

After examining the partition with both QT Parted and Windows 2000 install disk, both tell me that it s unknown or corrupt.
Anyone know how to fix it?
I don't think looking at the first bytes of the disk would be any use to me personally since I don't know what they're meant to look like.

[tomcat]

Before you start examining on corrupt partitions, try instead of
mount /dev/hda1 /mnt/windows -t vfat -r umask=0222
simply this:
mount -t vfat /dev/hda1 /mnt/windows

You have to put the mount command options and filesystem (-t vfat) before the partition you want to mount. See "mount --help" or "man mount" in a terminal.

[tejas]

Use this iff you've given up all hope:

fsck /dev/hda1

this will check the filesystem for errors, possibly rebuild the FAT

however, it will also wipe out parts of your system as 'unrecoverable' and suck, so use with EXTREME CAUTION

[spiritofcat]

After making a copy of the bad partition onto an external USB hard drive, using

dd if=/dev/hda1 of=/dev/sde5

I have now tried to repair the filesystem using fsck.
The command I used was this:

dosfsck -a /dev/hda1

and the result was this:

dosfsck 2.10, 22 Sep 2003, FAT32, LFN
File system has -47 clusters but only space for 131582 FAT entries.

It doesn't seem to have fixed anything.
Any ideas on what to do now?

[tashirosgt]

My 2 cents is:
If you are trying to recover a Windows partition, you would probably be better off using Windows tools. So ask Window's experts about this problem. (And ask them if you can install XP on a FAT32 partition. Does the installation give you that choice? With unformatted drives, the only choice I saw was for NTFS.)

If you want to recover the partition using Linux methods, then study the format of a FAT32 partition and start looking at what your partition has (byte-by-byte). I'm not saying this as one who already knows this format, but rather on the general principle that one usually can't fix complicated things that one does not understand. There are probably web pages that document the FAT32 format in great detail.

I'm having problems trying to mount my Fat16, basic DOS controler of Windows XP. See cause I had to wipe out my Linux part for the 4th time and in the process I wiped out the grub which overwrites the mbr with that grub crap. But if I'm a noob at Linux and was suffering some security issues cause I left some ports open and got wiped out. Grub screws everything up when i wipe it out. I've called around to a few places and they told me to do a program called Virtual PC from Windows XP if your Windows primary. Right now I'm trying to mnt the Fat16. Anyone know how to do that?

[Seve]

Originally Posted by KRAZYBASTID

I Right now I'm trying to mnt the Fat16. Anyone know how to do that?

Hello:
I am assuming you talking about mounting it is FC?
if so, then open a terminal and log in as root using su -
then type
mkdir /mnt/fat

then edit your /etc/fstab
and add
/dev/hdXn /mnt/fat vfat users,defaults,umask=000 0 0

save, exit and reboot and you fat drive should be automounted under /mnt/fat

Seve

Look I ain't a cooperate monkey for either one if you know what I mean. I think both operating systems are just fine. Why do people slam Windows so much, I mean who care us. Thanks for your advice it was very helpful.

[Jongi]

If you have your XP install disk, boot with that and choose the option to repair an installation. If it picks up the XP install, then at least you will know that you still have hope with it.

You can then run a chkdsk /f in recovery mode (I think it allows you to do that) and that should hopefully mean you are able to mount the FAT32 drive in FC and then be able to backup any important data you have.

All FAT32 is is support for the older Windows OS's the important one is FAT16 which is the basic DOS handler. NTFS doesn't need FAT32. I called around to a few places in my town and people told me FAT32 isn't nessesary in XP FAT16 is the backbone of NTFS.