Bitzer holds patents for inventions including the plasma-display panel, the binary-weighted solenoid, a high-quality modem, and new satellite communications techniques. The creation of the PLATO computer system, the first system to combine graphics and touch-sensitive screens, is the hallmark of his efforts. wikipedia 
Notes from An Interview with Donald Bitzer by Sheldon Hochheiser on
19 February 1988. pdf
quotes
The 1064 was a million dollar machine. It was a wonderful machine in its day. Seymour Cray did a great job designing that machine. Now that got us connected and working with CDC.
With that we were able to gather enough information with PLATO III to develop 5000 hours of lesson material. We taught 30 courses in different areas. We accumulated close to 100,000 student hours experience. Today we accumulate 5000 terminal hours per day. PLATO III was so useful that we didn=t shut it down until after PLATO IV was running for about three or four years.
Apart from machines, did Control Data seem to develop a real interest in what you were doing in terms of something with commercial potential? BITZER: That happened with the PLATO IV right off. They involved a significant number of people on the project. They had engineers looking at terminal designs. Others were integrating the computers into the system. How will the machines fit together? Some were involved in software development with us. That started almost as soon as PLATO IV was in operation using several hundred terminals.
By this time, most of the substantial work had been completed. It was an evolutionary process. It still continues, but most of the work had been completed. What was really left to do was advanced terminal designs. The first PLATO IV terminal did not have a microprocessor. It was a hard-wired terminal and is still being used today on our system. The new PLATO terminal, which is what we call PLATO V -- the plasma display terminal -- had an 8088 microprocessor on board. Jack Stifle was the key person on both of these terminal designs.
When we first designed communications for PLATO there were no standards. We designed the system to provide the most efficient transmissions. Characters were six bits long. The word length was twenty bits. The twenty bits were divided into eighteen bits of information, one bit of parity for error detection, and one bit to indicate if those eighteen bits of data were for display or what we called control information.
CDC would try to force authors into certain standardizations to fit into CDC standard. The UI authors said, "You don't understand anything about education. If you do that you will ruin the educational content or pedagogy." They got into some fights over certain standardizations. Some authors became completely uncooperative. CDC made some serious mistakes.
For example, they wanted to create a physics curriculum for some undergraduate science courses. UI had already done an excellent job of producing physics curriculum. It is still in use today. We've run a thousand students a year through it. It's very successful. The people who did that would have been very happy with just a few dollars in royalties. They didn't write the lessons to make money.
That's the fundamental difference. In the end they may not have done that well for all that they do for trying to serve a social need. They've got to make a profit. They've got to be profit motivated. I don't have to be profit-motivated, but I have financial limitations too.
Unfortunately they used capital to start some PLATO projects we could have done for them. They found out that was a mistake and backed off. If they ever decided again to start some new PLATO activity, they could spend a lot less money working with the University. This is the way we started originally. I think that they could do better and it could be an exciting relationship again. Nothing would make me happier.
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PLATO was so far ahead of its time in hardware alone that it attracted authors that wanted to teach, wanted to show what was possible, wanted to discover what was possible for themselves. It wasn't an investment, it was a journey.
See Programming Paradigms along the journey.