Here is what you need to write MIDI software in REXX:

1).You need the Reginald REXX Interpreter.

2).You need the "RxMIDI" add-on DLL. You can download it from the above page.

3).You need the MidiFile DLL and GenMidi DLL files, available where you got RxMIDI.

You can download the above items from the REXX User's web site. Someone wishing to run a script you write will also need to install the above 3 items.