What is the relationship between Foaly and Root?

Though Root is Foaly's commander, it is easy to see that Foaly feels on an even footing with Root. It seems that Foaly's knowledge makes him feel that way. Foaly runs the computer room so he is the one who sees all of the action which he reports to Root who then makes the decisions. Foaly plays with Root though perhaps because Root seems always to be upset. Foaly makes fun of Root's fat and yells at him about smoking. Root listens intently to everything Foaly says but often retorts in a sarcastic manner. The banter between the two is often funny and neither seems offended by it; instead, they both seem to thrive on it.