When you have a double FMGC failure (happened on one of my flights) you could be pleased to have a written record up to the previous waypoint, as I was.
Jep chart was open, but just after the failure our position, just off west coast of Italy, was right on a corner of the chart with no worthwhile overlap to the other joining 3 corners. Checklist, hand fly, chart unfolding & frequency change was interesting exercise. Also great to be day flight visual conditions.