that does take a lot of capacity. >> you have to delete and add more. i don't see any real significance for the deleting of files. >> or if you thought in some way you are hiding it? >> there is that possibility but it is so normal. it is just almost like -- >> i think really what we are saying is that the computer forensic experts are going to have to figure that one out. >> they are looking at that and trying to retrieve the lost data. i'm sure they are also looking at lower data that wasn't lost, about where he was simulating flights to and what kind of operations he has been doing. one other ski bit of information, this 12-minute gap between when the pilot, co-pilot, someone in the cockpit changed the computer settings, 12 minutes later, the last point of vocal contact. martin, i understand you have a demonstration to help us better understand that. >> mitchell, if you would, put