Grab a copy of "The little Schemer" (Daniel P Friedman and Matthias Felleisen) and a pencil and you can skip the phone and the notebook - oh and learn scheme of course.
If I was a programmer I would probably pickup a Dell Netbook, install OSX on it, and use that as my learning tool. I appreciate your objective, but I think that calculator is a step backward. Maybe since I'm not a programmer, I'm missing something.
lol, I did read---skim it but I guess I just mentally correlated that picture with the old Ti-8X calculators that people (and me) use to program on. My bad, it's Friday. :)
On a random off-shoot: is there something analogue (e.g. an abacus) that can be used for logic games or calculations that would fit in a pocket (and require no electricity)?
A few scraps of paper and a pencil! There are countless books of logic puzzles around, or you could just brush up on your maths and prove a simple lemma or two, if that's your cup of tea.
Travel light but make sure you travel.