Also, on newer airbuses, in case of dual FMGC failure, we have a "Nav Backup" that basically uses the IRS (ADIRUs) to keep your flight plan, waypoints, etc. It permits to continue the route, and basic management. Better than simple raw data. Of course for the approach itself you should use navaids on raw data.
Not usable in case of dual MCDU failure, however.
Regards