I'm pretty sure a filesystem from back then should be mountable-- the filesystem Linus implemented for the first iterations of Linux was the MINIX filesystem,

I'm pretty sure a filesystem from back then should be mountable-- the filesystem Linus implemented for the first iterations of Linux was the MINIX filesystem, and there's still a kernel driver for it [1]. I don't have a filesystem from back then to actually try it, though. [1] http://lxr.free-electrons.com/source/fs/minix/ http://lxr.free-electrons.com/source/fs/minix/