The Casio SF-8350 Digital Diary is an “all-in-one” gadget from 1993. A whopping 64 Kb of RAM and double batteries (so that one could be replaced without losing data). Functions like address book, calculator, world time, notes, alarms, etc. Compare with the Sony Ericsson Xperia Smartphone from 2008. Fascinating to see that the Casio had retained data, I haven’t been using it for over 10 years.