jahc wrote:
FAT partitions eh.. is there anything stopping me from purely using FAT partitions? or any disadvantages? This sounds like the solution to my multi-OS problem. I would like to be able to access all files from all OS's.
The big one is the lack of ownership and permissions fields in the filesystem- you can run Linux off FAT, and some embedded implementations no-doubt do, but you'll have a much easier job taking advantage of security with the 'standard' (ext2, ext3,

) FSes. Those also get more reliability testing in general, their fscks (or fsck-equivalents; again, I'm a BSD user here) have a higher chance of working properly, etc.
One thing to hold out hope for is UDF - it's no panacea, and 'tuned' more for removable media, but it's poised to *eventually* be the lingua-franca we sorely need. Meanwhile, you can try to run as many things as possible under a single host OS (MOL needs Linux up, after all), rig up the 'virtual' networking properly, and run a network filesystem like SAMBA, NFS, Appletalk??, or WebDAV (the last being the up-and-coming standard, well-supported by various Linux tools and the OS X Finder, though it's a bit of a mindf').
Then, until we have a BSD available on the PPC/Mai/U-Boot platform, you only have to worry about Linux<->OS4 (and maybe Linux<->MOS), which should at least go one way with the Linux AFFS drivers.
FAT partitions, with their long-filename headaches, fragmentation issues, etc, are really more trouble than they're worth these days. If you're going to use one, I'd say put it on a CF card or Pen Drive, and spare the layout of your HD; it's still the pidgin-of-choice for those devices, and then you have the excuse that you might someday unclip it and sneakernet it elsewhere. Or if that's too expensive, sacrifice a $10 surplus drive to the task- sure, it seems wasteful when you could do it the 'skilled' way, but you'll be happy when you grow sick of the kludge and won't have to backup 80gb to repartition.