Index chamber
From Halopedia, the Halo wiki
The Index Chamber is a vast room within the core of every Library on each Halo. It is the storage place of the repository of all Forerunner knowledge and study of the Flood, the Index. A T-shaped object of similar size to a human forearm. The Index is both a store of information and the key to a vast, immensely powerful, Galaxy culling superweapon, the Halo system.
At the very center of the Index Chamber can be found the Index[1]. Suspended in mid-air by unseen forces out of reach of trespassers and Flood outbreak. It can only be reached via a vast anti-gravity powered lift that remains docked, four to five levels above the floating Index[2].
This lift may require the authorization of the Installation's Monitor in order to be activated. Thus starting the process of retrieving the Index and the final act of activating the Halos and wiping the Galaxy clean of sentient life.
