Hidden Memory?

Palm TT,

when a file be it a notepad, to-do-list, doc 2go etc is deleted, does it actually get deleted? I mean is there a similar problem with like Windows where even if u delete a file via 'delete' or 'delete+shift' itcan be recovered via many means such as norton file recovery etc, can data be recovered in the same ways in Palms, both on board as well SD cards? Is it over written, if so, after what period of time? is a emp file created, what happens to the data after it is deleted, is it all flash memory? lot of Q?

thanks again