compat_ultrix —
setup procedure for ULTRIX compatibility on MIPS and VAX
  architectures
NetBSD/mips and NetBSD/vax
  architectures can run Risc ULTRIX and VAX ULTRIX executables, respectively.
  However, you have to worry about the legal issues of ensuring that you have a
  right to use any ULTRIX binaries on your machine.
Most executables will work. The exceptions include programs that
    use proprietary, ULTRIX-specific features (LAT, CI support, DECnet support)
    and various system calls, ioctl()'s, or ULTRIX
    kernel semantics that are difficult to emulate (e.g. ULTRIX packetfilter) or
    buggy (e.g. ULTRIX NIS).
All ULTRIX executables are static, so no shared libraries are
    required for ULTRIX compatibility. However, ULTRIX is based on a
    4.3BSD alpha release. ULTRIX commands and libraries
    are often much older than their NetBSD or even SunOS
    4.x equivalents, and may require incompatible configuration files.
Set up resolv.conf and svc.conf
  as below:
  - # mkdir -p /emul/ultrix/etc
- 
    
 
- # cd /emul/ultrix/etc
- 
    
 
- # egrep 'domain|nameserver' /etc/resolv.conf > ./resolv.conf
- 
    
 
- # cp -p /usr/share/examples/emul/ultrix/etc/*	./
-  
 
The ULTRIX resolver library only understands domain and
  nameserver lines in
  resolv.conf(5). You should
  create a copy of /etc/resolv.conf containing only
  those commands and put it in
  /emul/ultrix/etc/resolv.conf. Note that the domain
  search order used by ULTRIX executables may not be the same as native
  binaries; there is no good way around this.
ULTRIX uses /etc/svc.conf to select an ordered search of
  NIS, Hesiod, or local flat-file mappings. You should create an
  /emul/ultrix/etc/svc.conf specifying either local
  files or bind (DNS) lookups for all ULTRIX name services.
RISC ULTRIX NIS (YP) is known to not work. The ULTRIX NIS libraries have a
  consistent endian-ness bug. ULTRIX NIS client will not inter-operate with the
  NetBSD
  ypbind(8) process. The only
  workaround is to use /etc/svc.conf to disable NIS
  (YP).
The ndbm hashed-password file used by ULTRIX are incompatible with
    the db hashed-password file used by NetBSD. There is
    no good solution for this. NIS would be a good one, if ULTRIX NIS
  worked.
The API used by Xservers to talk to the kernel is currently
    compatible with ULTRIX 4.1. An implementation of the ULTRIX 4.2 Xws
    interface (used by X11R6) is in progress.
A complete list of things which fail to work in ULTRIX
    compatibility mode should be added here.