Tuning pianos, harpsichords, etc

I visited Alex yesterday. He has a harpsichord which is badly out of tune. We spent some time tuning it (I have some knowledge of how to do that). We got the "home octave" (starting at middle C) reasonably in tune, and the octave below that somewhat in tune, with some doubtful notes (the usual suspects, F#, B natural)

Then we talked about bringing my Macbook over to tune it properly with tuning software.

This turns out to be not necessary. It can be done with a $4 app for my iPhone!.