Xnp2 is a port for UNIX with X11 of "Neko Project II" PC-9801 emulator.
You need disk image(s) to run the system. And you need font map to display Kanji correctly.
These resources can be found at http://www.jcec.co.uk/pc98_util.html.
Xnp2 also supports MIDI. This requires fluidsynth and a soundfont.
Run the script below before starting the emulator.
[ -e /dev/midi ] || mkfifo /dev/midi
fluidsynth -is -a alsa -m oss -i /path/to/sf2
Make sure you have write permission to /dev/midi.
After that, in Device -> MIDI option, set MIDI-OUT as /dev/midi.
There are two executables in the package, xnp2 and xnp21. xnp21 emulates with IA-32 emulation.