Source : Free On-Line Dictionary of Computing

RT-PC
     
         RISC 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  It was withdrawn from the marketing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)