In the domain of MIDI production virtual tracks refer to tracks that exist only in MIDI (as opposed to on a tape machine). A technique that became very popular in the 1980's was to never record MIDI instruments to tape. Instead a MIDI sequencer is synchronized to the tape machines and the MIDI tracks are always "flown in" and mixed in real time as if they are live instruments playing along with the tape. The sequencer stays locked to the tape machine throughout all tracking, overdubbing, and through mixdown. This allows artists to have many more effective or virtual tracks available than what their tape machine would otherwise allow.