For both Otari and Studer, I have been involved with software development of automation and control systems for audio mixing consoles.  These have been Microsoft Windows based application development projects designed to record and play back real time movement of motorized faders, knobs and soft switches slaved to LTC or VITC time code.
 
These systems would allow the mixing artist to perform a mix, recording all the moves of the faders, knob and switches.  When the song was played back, all controls would move as before, allowing the mixer to touch any control and update the mix.  This work was primarily C++ based development.  
 
This was my first venture into Test Driven Development.  I had written hundreds of N-Unit tests.  There is no better feeling than to make code changes, run the tests and watch the green bar grow! I eventually handed this code off to another engineer who greatly appreciated the test cases as it was five years of development in total.
 

The development with Otari was done with my engineering team here in the US and the Studer development was done as an independant consultant working with an engineering team in Switzerland.