This is a question I've found myself answering several times over the years - why dosn;t a Pocket PC retain it's data when the battery runs down completely. This article from the Windows Mobile team blog gives a terrific explnation as to Why Persistent Storage Is A Good Thing as there are some significant benefits beyond persistent storage - such as much better battery life. Well worth a read if you want to understand some of the under the cover stuff in Windows Mobile 5 (for Pocket PC) - this has been around since day 1 on Smartphone of course.