just some documentation on old systems:
ULTRIX 3.1D
ULTRIX 3 VAX
ULTRIX 4
OSF/1 1.0
SunOS 3.5
SunOS 4.0.3c SPARC
Solaris 2.0 SPARC
Solaris 2.4 SPARC
Sony NEWS-OS 3.3
SunOS 4 network boot howto
IRIX 3.3 installation
gcc-2.95.3 libIO patch for ULTRIX
SCO Openserver 5.0.7 installation
SCO UnixWare 7.1.4 installation