Hi

> The application where the server has been embeded must run from CD- ROM,

so the database file will be *ALLWAYS* opened in the read-only mode.

Okay. In this very special case, there is no problem in using multiple
engines on the same GDB file.
Therefor it should be possible to avoid the lock. But I cannot tell you how.
Check firebird-devel on this.

Regards,
Steffen