RT-PCRISC Technology Personal Computer. (Commonly, but incorrectly, known as the "PC-RT", later changed to just "RT") {IBM}'s first {RISC}-based {Unix} computer. The RT-PC was the predecessor to IBM's {RS/6000}. It ran {AIX} 1.x and 2.x and had a {PC-AT} bus and IBM's {ROMP} {microprocessor}. It was withdrawn from the marketing around 1989 or 1990. (1995-04-06)