Yes Kurzweil does show a bend in the real data in several cases. I did not try to duplicate that in my plots, I just did straight doubling every year.

I think any bending in the log scale plot could be fairly called acceleration.

But just the doubling itself, while it leads to ever-increases step sizes, is not acceleration. In the case of computer performance it seems clear exponential growth of power produces only linear growth in utility.

I feel this point is not made clear in all contexts. In presentations I felt some of the linear scale graphs were used to "hype" the idea that everything was speeding up dramatically. I think only the bend points to a "speeding up".