MidiDrums is a software MIDI drum machine. You can use it to drive a software or hardware synthesizer to generate percussive sounds. It supports customizable "drum maps" to link MIDI notes with sounds, comes with "General MIDI", "Roland GS", "Yamaha XG" and "Yamaha Motif Rack ES". Each document can contain up to 40 patterns, each made of 1-8 quarter notes, each divided in 1-24 beats. A document can also define a single song, assembled with the available patterns. Documents are archived as XML files. Each document can refer to different devices and to a different drum map. Beats can have some "swing", i.e. a randomly applied time variation within a given percentage range. Each "event" has user defined probability and velocity ranges. MIDI files can be imported with reasonably successful results. Playback start, stop and pause, as well as the current mode, pattern and tempo can be controlled via MIDI control change messages. Can act as a MIDI clock sync master.