We'll get a chance to go through this [Apple versus Microsoft debate] again in phones and music players. There's no chance that the iPhone is going to get any significant market share. No chance. It's a $500 subsidized item. They may make a lot of money. But if you actually take a look at the 1.3 billion phones that get sold, I'd prefer to have our software in 60% or 70% or 80% of them, than I would to have 2% or 3%, which is what Apple might get.

Ultimately progress is measured sort of through the eyes of users.

I meet with Satya [Nadella] what probably amounts to four or five times a year - either to brainstorm something or just as a shareholder, we'll sit down and chat. That's always quite helpful for me and hopefully him in terms of thinking things through. I still have a number of friends and colleagues who occasionally want to brainstorm or chat about something, and that's always fun.

It's how tenacious you are that will determine your success.

The company I invested in is probably a leader in that area. They're a company called Second Spectrum, which happens to be based in LA but was started by two USC computer-science professors. It's filled with guys who love sports, who played sports, but really look like programmers.

Great companies have high cultures of accountability, it comes with this culture of criticism I was talking about before, and I think our culture is strong on that.

Computer science is the operating system for all innovation.