I had a simular sampler/midi-combo (think it was an AMAS, but I can't remember 100%). I composed a few tunes using MidiTracker which is a really nice tracker for midi, you'll find it on AmiNet. Used Audiomaster for sampling.
I also had an external hard-drive which had a connector for a power supply but was able to run without one plugged in (allthough a bit shakey).
