A fundamental difference between the Windows Phone 7 operating system and its older Windows Mobile operating system cousin is the way files are handled on devices. Windows Phone 7 does not expose its file system to the end user, so there isn’t a way for you to browse, sort or manage all the files that are stored on the phone from a single application. Instead each application plays within it’s own “sandbox,” which means each application operates, in many respects, as a stand alone entity within the windows phone operating system infrastructure. The application controls how users interact with its files. It is left to the application developer to provide options to users for retrieving, backing up, renaming, and organizing files and to provide ways for users to share its files via text message or email.
The Adobe Reader software that Adobe developed for Windows Phone 7 is missing some important options. The application does not provide a way to share PDF files that are stored on the phone with anyone else, nor is there a way to copy or back up PDF files from the phone to the web or to a computer.