Tell the OS when a card is ejected #98
Description
We need to be able to tell the OS when a card is inserted and/or ejected. This will allow it to invalidate its cache and rescan the card and all its volumes.
Perhaps add a unique_id field to the BIOS block device info API. The read/write API can then use that unique ID, and thus fail if the card is removed and re-inserted. Every time we find a card, the ID goes up by 1. We assume no-one will manage to remove/insert 2^32 cards without crashing or rebooting.