Why port to Linux and not to one of the free BSD
versions like 386BSD and its derivatives FreeBSD and
NetBSD (short: *BSD)? Well, that depends on your
application. If it was originally written for a
SystemV-based system as AIX, HP/UX or Solaris 2,
porting to Linux should be fairly easy. *BSD
lacks certain SystemV features (such as the termio
interface), and you'll have to carefully check the
amount of work necessary. On the other hand, FreeBSD
and NetBSD are maintained by a closed developers' team
(as opposed to the open and sometimes chaotic and
anarchic Linux developers' community), and e.g. for
FreeBSD there is only one so-called distribution
available per
FTP. You might want to mail
info@FreeBSD.org or look
on
http://www.cdrom.com/titles/freebsd.html.
By the way, the FAQ for comp.unix.bsd.netbsd.announce concerning the *BSD flavors says (short excerpt):
5. Where BSD and POSIX differ, 386BSD conforms by default to
BSD; Linux to POSIX. Furthermore, while both run mostly GNU
utilities, Linux tends toward the SysV flavor (e.g. init)
where 386BSD sticks with the BSD style. However, sources for
different flavors of utilities are available for both, and
both support compiler options which allow more BSD or more
POSIX semantics.
And later it says:
1) the 386BSD family started with BSD, and Linux started with
POSIX. NetBSD/FreeBSD/386BSD have been adding POSIX and System
V compatibility, and Linux has been adding Berkeley and System
V compatibility. So there's a good deal of overlap. But ...BSD
is still a better choice if you want to program in a Berkeley
environment and Linux if you want a POSIX environment.