Abstract: This metric is the ratio of the maintenance personnel who are actively doing the maintenance work (direct) to the maintenance personnel supporting the maintenance work (indirect). Direct personnel include those workers in the maintenance department that repair, maintain, modify or calibrate equipment.
MIDI (Musical Instrument Digital Interface) is a protocol designed for recording and playing back music on digital synthesizers that is supported by many makes of personal computer sound cards. Originally intended to control one keyboard from another, it was quickly adopted for the personal computer.
Some synthesizer, sampler, and sequencer modules don't include a keyboard, and are triggered via MIDI. Soft synths, samplers, and sequencers are digital versions for the computer. A MIDI keyboard connected to the computer is normally used to trigger the computer's soft synths, samplers, and sequencer. Computer soft synth and sampler programs are often as feature-rich (minus keyboard), but are significantly cheaper.