[TUHS] Is there a good, even definitive, list of reimplementations of the Unix kernel? What would good cut-off criteria be?

[Jeremy C. Reed via TUHS]

On Sat, 25 Apr 2026, Arnold Robbins via TUHS wrote:

> Clem Cole via TUHS <tuhs at tuhs.org> wrote:
>
>> [Keith wrote Nvi himself, which was often
>> said to be the tool that would never be replaced].
>
> For the record, he started with a vi clone named Elvis, and then
> turned it into a "bug for bug compatible" clone of vi.

Bostic contacted Steve Kirkendall for permission to use his ex/vi clone's
source code while he was writing nvi ---
probably to drive home the fact that it wasn't derived from
the original Bell Lab's ed (via vi).
``As far as I can tell, he didn't copy any of elvis' source
code into nvi, however elvis' source code does clearly document
the quirks of each command in an organized way and I'm sure he
found that useful,'' Kirkendall later said.\cite{kirkendall1}
Bostic's nvi documentation stated: ``Without his work, this work
would have been far more difficult.''

(per my personal correspondence in Nov. 2010)

As for Elvis ... 386bsd-0.1 and NetBSD (March 1993) included Elvis.

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