Parallel Element Processing Ensemble

The Parallel Element Processing Ensemble (also known as PEPE) was one of the very early parallel computing systems. This computer was originally designed by Bell Labs and built in the mid-1970s by Burroughs Corporation at their Great Valley Labs engineering facility in Paoli, Pennsylvania. The original goal was to build a computer system that could simultaneously track up to 288 incoming ballistic missile warheads. 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evolved into the Burroughs Scientific Computer for commercial sales, but a lack of sales prospects led to it being withdrawn from the market.

The design featured an array of 288 (8 × 36) identical processing elements and associative addressing. Each processing element contained a minimum of control logic, the bulk of the control being concentrated in a common control unit. The control unit read instructions from memory, decoded them, and issued them to all processing elements simultaneously so that the elements were required to execute exactly the same instruction at exactly the same time. The elements were capable of executing a complete single address instruction repertoire permitting any desired arithmetic or logical operation.

A Burroughs B1700 computer system was used as a test and diagnostic computer. A custom software package, called TRANSET, which executed on the B1700 was used to debug and maintain PEPE's processing elements.

Burroughs delivered PEPE to the Ballistic Missile Defense Advanced Technology Center (part of US Army's Strategic Defense Command) in Huntsville, Alabama in 1976.