John Carmack, in a post on Facebook:

I was brought in to talk about the needs of games in general, but I made it my mission to get Apple to adopt OpenGL as their 3D graphics API. I had a lot of arguments with Steve.

Part of his method, at least with me, was to deride contemporary options and dare me to tell him differently. They might be pragmatic, but couldn’t actually be good. “I have Pixar. We will make something [an API] that is actually good.”

It was often frustrating, because he could talk, with complete confidence, about things he was just plain wrong about, like the price of memory for video cards and the amount of system bandwidth exploitable by the AltiVec extensions.

But when I knew what I was talking about, I would stand my ground against anyone.

When Steve did make up his mind, he was decisive about it. Dictates were made, companies were acquired, keynotes were scheduled, and the reality distortion field kicked in, making everything else that was previously considered into obviously terrible ideas.

His post reinforces what we know about Steve Jobs, while underlining their own relationship — it’s well worth reading.