The Parallel Element Processing Ensemble (PEPE) was one of the very early parallel computing systems. Bell began researching the concept in the mid-1960s as a way to provide high-performance computing support for the needs of anti-ballistic missile (ABM) systems. The goal was to build a computer system that could simultaneously track hundreds of incoming ballistic missile warheads.[1][2][3] A single PEPE system was built by Burroughs Corporation in the 1970s, by which time the US Army's ABM efforts were winding down. The design later evolved into the Burroughs Scientific Computer for commercial sales, but a lack of sales prospects led to it being withdrawn from the market.