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

[John Cowan via TUHS]

On Sun, Apr 19, 2026 at 11:25 AM Paul Winalski <paul.winalski at gmail.com> wrote:


PECOFF is a classic case of Microsoft's adopt-then-extend philosophy.

To be fair, COFF was a rather inflexible format, though not so much as
a.out.  Pretty much every OS that ran on MIPS used ECOFF, and AIX used
XCOFF, both of which were extensions of COFF made even before MS made
its own variant.

https://en.wikipedia.org/wiki/Comparison_of_executable_file_formats is
what it says on the tin.