Converting Korg 5 file format

Archived from groups: rec.audio.pro (More info?)

I'm not in the music field, but am trying to help out a musician. She
was having someone lay tracks to produce a recording when the Korg
Triton was stolen as part of a drug heist.

All she has left is a diskette with the following files: a) a small
..ksc file, b) a larger .sng file, c) and a much larger .pcg file.

Are these formats proprietary, and can they be converted into an open
format such as .wav? Which of the three files do I need to do that? I'm
sorry for my ignorance here, but I'm trying to help someone as best I
can.

I am looking for a format conversion tool, preferably open source to
run under Linux, but not necessarily.