As Firebird 2.5 proyect moved the embedded server from SuperServer to SuperClassic, now when we open a database file using the embedded server it is opened as a full shared file.
We found that this is going to be the source of problems. For example, we found users that are doing backups while the server is using the database file; then, if we try to open this database our application crashes (we can't understand why).
As Dmitry suggested to me, I tried to lock the file (I used LockFile Win32 API) but then Firebird can't open the database file.
So, I want to suggest to add an option for entirely locking the database file while using it.