Apple continued to rely on innovative design to remain competitive in the 1990s It introduced the very popular PowerBook notebook computer line, as well as the unsuccessful Newton personal digital assistant. Scullery was forced out and replaced by Michael Spindlier. After a difficult time in the mid-1990s, Spindlier was replaced with Gil Amelia, the former president of National Semiconductor. This set the stage for one of the most famous returns in corporate history.