You reach one of the tower's computers. Nobody really knows what the data stored in them is, or how to read the language it's in. Only a few glyphs have been actually decyphered, entirely through informed guessing. The possibility of being wrong still exists. They seem to be numbers, two negatives, two positives.
It appears to describe events that will happen, and have happened, in geological timescales, with the most recent one having happened only eighteen years ago. That number stands out among the other four.
You can't think of any events of extreme significance that might have happened around that time. What were the creators of this machine waiting for, and why are they not around to see it?
Right. You should focus. You were looking for your father.