How do you usually take notes for reading source code of a big software

Question

For big software, take notes is useful for understanding the big picture.

How you take notes? With pen/paper, or just a notepad; and what you usually will write for note?

Answer 1

If you're a team: install a wiki and contribute all your discoveries there. Will preserve the knowledge for eternity and sharing it will be very easy.

Answer 2

I generally note down the Important methods. Also mark important logic part part in IDE.