Early computer-music programs typically did not run in real time, although the first experiments on CSIRAC and the Ferranti Mark 1 did operate in real time. From the late 1950s, with increasingly sophisticated programming, programs would run for hours or days, on multimillion-dollar computers, to generate a few minutes of music. One way around this was to use a 'hybrid system' of digital control of an analog synthesiser and early examples of this were Max Mathews' GROOVE system (1969) and also MUSYS by Peter Zinovieff (1969).