I bought a 320GB external harddrive to backup my data/webpage/music, etc. I partitioned the drive into 3 partitions (100GB/100GB/100GB), and formatted them as fat32 in windows.

After 2 weeks or so, I went back to update my backup using linux, and after successfully mounting the partitions I found a problem. I get:
# cd /media/ExternalMusic
# ls MusicFolder
ls: MusicFolder: Input/output error
# file MusicFolder
MusicFolder: ERROR: cannot open `BackupMusic' (Input/output error)
# dmesg tail
[32666756.849000] FAT: Filesystem panic (dev sdb6)
[32666756.849000] fat_get_cluster: invalid cluster chain (i_pos 0)
[32666756.849000] File system has been set read-only
[32666757.529000] FAT: Filesystem panic (dev sdb6)
[32666757.529000] fat_get_cluster: invalid cluster chain (i_pos 0)
[32666757.529000] FAT: Filesystem panic (dev sdb6)
[32666757.529000] fat_get_cluster: invalid cluster chain (i_pos 0)
[32666757.529000] FAT: Filesystem panic (dev sdb6)
[32666757.529000] fat_get_cluster: invalid cluster chain (i_pos 0)

I did some research and found fat32 doesn't support over 32GB of space, so I redid everything using 30GB partitions. After transferring everything back again, it seemed like it was working. Now, 2 days later, exactly the same problem.

I like windows on my laptop, and I like linux on my server/desktop. How can I backup my winxp system AND my linux system on the same external hard-drive?

Thanks all!

Maybe make 2 equal partitions on your external HDD?

One for windows, formatted with your preferred windows filesystem.
The other for linux, again, formatted with your preferred linux filesystem (ext3 is mine)
Then just use them, from the appropriate OS of course.

You'll still be able to see your windows backups from your linux PC, the reverse might not apply.

In general, backing up linux files to a windows filesystem is a BAD idea. Much, useful, information is lost when you do this as windows has no concept of ownership, the group the file belongs to mtime etc. (Unless you tar up the files first, but FAT32 cannot cope with a single file of more than 4GB, and many of my linux backups exceed that).

Linux can read NTFS and even write it pretty well nowadays. There is also an ext3 driver for Windows.