allowing you to put up dialogs such as
+--------------------------------------------------------------+
| The application Frobnicator is trying to access a file on a |
| device that is not available right now. To continue please |
| attach the device |
| |
| <logo> 4GB file system labeled "Raptor" |
| Sandisk Cruzer Micro (in small grey font) |
| |
| [Cancel] [Continue] |
+--------------------------------------------------------------+
(for removable media it would say "insert the media" rather than
"attach the device")