Quoting Bruce Evans,

> >FreeBSD's is actually taken from NetBSD originally, and the two have
> >diverged somewhat.

> Actually, FreeBSD's Linux emulator never had anything to do with the
> NetBSD one, at least according to my memory and the cvs log messages.
> For comparison, FreeBSD's original ibcs2 emulator was mostly replaced
> by the NetBSD one, and ithis is indicated by 110 lines of log messages
> containing the string "NetBSD".

I think the history is something like this: someone in FreeBSD actually
started working on Linux emulation before someone in NetBSD (that'd be me)
did. I started later, unaware of his effort, and finished sooner, so NetBSD
was the first to have Linux emulation.

FreeBSD later came out with their Linux emulation, and while it's not an
import of the NetBSD code, I do think that in the later stages, the
NetBSD code was used as a reference at least. Some FreeBSD people
indicated that this was indeed the case.

The only major difference in functionality now, is that the NetBSD
code handles svgalib executables. There may be other, minor differences.

- Frank