UFS, I assume. Linux can read it, see /usr/src/linux/Documentation/filesystems/ufs.txtI have a friend who did it but he had to make a FAT partition to share a partition because linux does not write on usf. Is this statement stilltrue? Can macosx r/o on ext2-3?MacOS can't read ext2/ext3. But Linux can read USF
You can even install OS X on UFS, yet I don't know if it is the plain UFS from FreeBSD which Linux can read/write or something Apple modified and/or screwed up somewhat.
Also MOL can't boot an OS X that is on a UFS partiion.
and read/write to HFS+ (YOU SHOULDN'T!), but you can if you want :)
Well, the new HFS+ patch from <http://www.ardistech.com/hfsplus/> seems to work real good also for write operations. It's in the benh tree by now so no need for manual patching.
-Thomas