"time-machine style backup" seems to be a marketing term, not a type of backup.
Do you mean a hard link style backup? Where diffs are never stored, you just keep making hard links of the files? And if they change even one byte you store the file fresh?
There are plenty of solutions to this, the simplest being storing reverse diffs - so the latest file is stored plain, but older ones can be generated from diffs (since doing so is rare).
You can also use modern filesystems like btrfs that can do COW and block de-duplication and store only changed blocks in such a way that the file appears to be complete, but actually stores only what changed.
Do you mean a hard link style backup? Where diffs are never stored, you just keep making hard links of the files? And if they change even one byte you store the file fresh?
There are plenty of solutions to this, the simplest being storing reverse diffs - so the latest file is stored plain, but older ones can be generated from diffs (since doing so is rare).
You can also use modern filesystems like btrfs that can do COW and block de-duplication and store only changed blocks in such a way that the file appears to be complete, but actually stores only what changed.