Like the large hybrid computers of the 1950s and 1960s, either the analog or digital coprocessor can operate independently as an analog or digital computer. Both can operate simultaneously in parallel as well, with either the digital coprocessor utilizing the analog for subroutines, the analog utilizing the digital for repetitive operations, or both operating separately. Programming and control of both coprocessors is performed by the host computer using the high-level language FORTH. In the case of the digital coprocessor, the host computer compiles the FORTH program in the machine language of the coprocessor, which is then stored in common RAM. Programming of the analog coprocessor is accomplished by using extensions of the FORTH language to address latching buffers which control the digital coefficient potentiometers, analog switches for programming and scaling, and input and output summing amplifiers. Additional extensions of FORTH control the numeric data processor and provide mathematic functions such as sine, log, cosine, and exponent for the digital coprocessor.
Numerous interfaces are provided both between the coprocessors and host computer, and the coprocessors and the physical world. The purpose of the former is to enable the host computer peripherals to be used by the hybrid for display, storage, and printout. The latter enables the hybrid to interface either coprocessor to both analog and digital inputs and outputs. In addition, through various interconnections using ADCs and DACs, the hybrid can operate in bilateral mode, or in unilateral mode. In the unilateral mode, the analog coprocessor can precede the digital, or the digital can precede the analog.