IBM AS/400 (1988)
The AS/400 moniker covered a wide range of minicomputers, from the early tower system pictured here to mainframe-size behemoths. The first models, introduced in 1988, were designed to replace IBM's earlier System/36 and System/38 lines. By 1997, IBM had sold half a million of them, making AS/400 one of the most popular "midrange" business computers ever made. The AS/400 line had a long run, ending in 2000 with a name change to iSeries, but many early-vintage AS/400s are still in operation today.