Brad Parker ported an old BSD Chaonet driver to Linux. From the README:

Chaosnet was an early networking protocol developed at MIT.  Near as I
can tell it was developed before TCP/IP, perhaps during the early
Arpanet NCP protocol days.  The protocol was supported by Symbolics
lisp machines as a native networking protocol.  Older machines (like
my ancient 3600) don't have TCP/IP support but do support Chaosnet on
Ethernet.  This is a port of some really really old BSD kernel code
to modern day linux.

I doubt anyone would want this code unless they have some old lisp
machines they are playing with...

I've tested this code with General 7.2 and 8.3.  It allows QFILE
transfers back and forth, which was my goal.  I also hacked the RTAPE
server code to do RTAPE support using a disk file instead of a real
file.  This is useful for archiving...

-brad

Just what I was looking for to make some backups.