I was working towards my PhD in machine learning with neural networks in 1990 and I tried to implement backpropagation in Occam in 1989. But gave up and tried u

I was working towards my PhD in machine learning with neural networks in 1990 and I tried to implement backpropagation in Occam in 1989. But gave up and tried using C* on a Connection machine instead. That did not work out well either so I finally wrote a simple C based implementation that ran distributed on a cluster of IBM RS 6000 workstations ( very well I might add) :-) Parallel computers of the late 80s were a mixed bag - they worked well for a few use cases but in general, they were troublesome and getting access was difficult and expensive.