My original point is: the "original reimplementation" thing just means that the creators of those system found the feature useful enough to implement it.
If those systems were UNIX-derived, it would not say much - after all they'd inherit the implementation together with source code or at least API design.
That's why it's important to mention those system whose codebase was very different. Like DOS (BTW, as already mentioned, DOS DID have minimal support for FS usage from TSR - the very hairy idea of InDOS flag)