Some of TempleOS actually reminded me of the MOAD[1], and even the Acme[2] editor a bit. The beauty of plain text is that it's trivial to interpret though (not unicode so much). Anything else and you need to start to worry about backward/forward compatibility, byte orders, etc... I imagine it's probably easier when you only have only one platform to think about though.

I liked the index concept. There have been more than one (successful) efforts to build a filesystem that fully supports indexing content, but they're generally implicit indexes. Explicit indexing via file content might be interesting.

I'm not sure what the real justification for running everything in Ring-0 is. I can't think of many reasons for anything more than minimal privileges to be a benefit.

[1] https://www.youtube.com/watch?v=yJDv-zdhzMY

[2] http://acme.cat-v.org/

A lot of the capabilities described for DolDoc, and for TempleOS documents in general, also exist in Emacs' org-mode, albeit of course in a rather different style -- inline images, hyperlinks to live searches as well as static content, and the like.

You can also embed code fragments of arbitrary length, in any or all of dozens of languages, and execute them inline with arbitrary input, including both other sections of the same document and the output of other code snippets therein. (TempleOS seems to have a similar capability, but of course only for the single language in which everything to do with it is implemented.)

It's a cliche, but Emacs really is almost like a LISP operating system disguised as a text editor. It's easily possible to use a computer productively using nothing else, if you devote a bit of time to learning how.