The machine was designed to solve fluid dynamics problems for the Ballistic Research Laboratory.

A single processor, called a PEM (Process Execution Module), in a HEP system (up to sixteen PEMs could be connected) was rather unconventional; via a "program status word (PSW) queue" up to fifty processes could be maintained in hardware at once.

In fact, only one instruction from a given process was allowed to be present in the pipeline at any point in time.

Constant registers were differentiated by the fact that only supervisor processes could modify their contents.

The HEP implemented a type of mutual exclusion in which all registers and locations in data memory had associated "empty" and "full" states.

Another component of the switched network was the sO System, with its own memory and many individual DEC UNIBUS buses attached for disks and other peripherals.

Ron Natalie (from BRL) and Burton Smith designed a new system out of spare parts on napkins at a local steakhouse and put it into operation in the course of the ensuing week.

The HEP's primary application programming language was a unique Fortran variant.

Mike Muuss was involved in a Unix port for the Ballistic Research Laboratory.

Although it was known to have poor cost-performance, the HEP received attention due to what were, at the time, several revolutionary features.