1987
The final version of the Midi Horn is built. This is a MIDI controller instrument based on a single board microcomputer and programmed in Forth programming language. Gary Nelson takes the MIDI Horn on the road with over 200 performances around the world. He uses the Midi Horn as the performance interface part of a 'hyperinstrument' consisting of a Macintosh computer, a set of digital synthesizers, and the software (Max/MSP) linking them all together. In a 'hyperinstrument' the controller does not necessarily play 'notes', it sends performance signals acted upon by a computer program composed to control how the music is played out.

After working with Forth Programming Language on the MIDI Horn I am impressed with its speed, compactness, and ease of use. The Forth language consists of a dictionary of words (subroutines) and several stacks for storing the subroutine data. Programming in Forth is a matter of building new 'words' by combining previously built words that are already in the dictionary, thus creating a hierarchy of words. The higher-level words can easily be tested by running their lower level components. Lower level words that deal directly with the processor hardware are easily built, even using assembly code if that is deemed necessary for speed.

The Ohio Scientific Microcomputer is upgraded in 1987 with a Forth based system (RSC Forth). The language is significantly extended with words that deal with the Hybrid Synthesizer, MIDI input and output, a Timer device, a new SID synthesizer chip, and all the devices used to control the analog synthesizers such as control voltage DACs and ADCs, pulse detectors and generators. The Hybrid Synthesizer interface is rebuilt with new waveform generators and timer control. Floppy drives are installed for user storage of programs. (RSC.pdf - 1.2Mb, RSC Code.pdf - 1.2Mb, Hybrid.pdf - 2Mb)[/color]