with the development of storage area networks and server farms of thousands of servers by the year the minicomputer had all but disappeared and mainframes were largely restricted to specialised uses the google server farm is thought to be the largest with a total calculation rate three times that of earth simulator or blue gene as of this is bull shit mainframe is still ibm's most profitable branch literally billions of dollars earned because banks and governments would never accept the inherent unreliability of pc farms also pc based clusters simply cannot have the vast i o performance traditional to mainframes which these big brothers require without tremendous i o bandwidht e g serve interactive users and six fully loaded atm circuits at the same time the cpu power is of little real world use