 During the 1970s, captive production, dominated by IBM's production for its own use, remained the largest revenue channel for HDDs, though the relative importance of the OEM channel grew.Led by Control Data, Diablo Systems, CalComp and Memorex, the OEM segment reached $631 million in 1979, but still well below the $2.8 billion associated with captive production.The 1980s saw the minicomputer age plateau as PCs were introduced.