What data can be lost when the battery is removed?
I recently damaged the power/usb port on my HTC Droid Incredible and have been removing the battery to charge it externally. In doing so, I did not seem to lose any data.
Today, when I replaced the battery, my Call History and Contacts were gone. Other apps, files, and data appeared to have been unmodified. Later when I removed and replaced the battery, the Call History with 3 recent calls and one Contacts entry I had just added were still in the phone.
(1) Does removing the battery risk losing data from Call History and Contacts?
(2) If removing the battery did not delete the Call History and Contacts, what caused them to be deleted?