What is the MiniDisc (MD) and What is the difference between the 60,74 and 80 min of MD?

The creation of the MiniDisc MD MiniDiscs were announced in 1991 by Sony as a disc based digital medium for recording and distributing consumer audio that is “near CD” in quality. In 1993 Sony announced MD Data, a version of the MiniDisc for storing computer data. There are two physically distinct types of discs: Pre-mastered …