First done as far as I can remember with Multics in the 1960s. The people who worked on IBM's canceled successor to the System/360 used it for System/38 in 197

First done as far as I can remember with Multics in the 1960s. The people who worked on IBM's canceled successor to the System/360 used it for System/38 in 1979, with capabilities, a feature which was dropped for the successor AS/400/iSeries/System i.