That explains the swab option to dd. :(
Hm? Maybe I’m missing your meaning here – I’m not sure exactly what the origin of that option truly is (though it is presumably something to do with endianness-conversion or similar I’d expect), but blindly swapping each pair of bytes doesn’t seem like it would be of much use in converting a filesystem. For that you’d need to very carefully byte-swap just the FS metadata, not file contents, and probably not even all of that (if you had, say, two adjacent single-byte fields, they would probably need to remain in place). On top of that, any fields larger than two bytes would also require additional processing.
Yeah, I hadn’t thought about byte fields. I was assuming that you’d then have to swab the file contents back, separately, but it still seems like the kind of thing that might have been useful when network file transfers weren’t always available.