Data crystal chip

Data Crystal Chips are a form of file storage device used by the UNSC. These data crystal chips are used for transferring "hard" data, meaning data that cannot be transferred over Slipspace or through a transmission because of the data's sensitive or complex nature. Examples of such data include AI data, navigation data, weapon technological charts, ect.

Uses
The Data Crystal Chip can be utilized for many things. Here are a few of its uses:


 * Carrying the Riemann Matrix for an Artificial Intelligence Construct, like Cortana or Deja.
 * Carrying star charts, maps, and other navigation data. These chips must be destroyed if contact is ever made with the Covenant, as per the Cole Protocol. This did not happen aboard the Circumference during The Battle of Reach and Blue Team were sent to destroy its Data Crystal Chip.
 * Carrying sensitive data, such as intelligence. Dr. Catherine Halsey had compiled two of these with all known information on the Flood.

Appearences
The Data Crystal Chip was seen extensively throughout Halo 1, as the Master Chief uses it to ferry Cortana between his armor and other computer systems. However, it is not seen or mentioned at any point during Halo 2. The Master Chief is instead seen directly downloading Cortana via physical contact.

If the leaked Halo 3 videos are to be believed, then the Data Crystal chip is set to reappear in Halo 3. In this game, it appears to be inserted into the back of the MJOLNIR Mk VI helmet (as opposed to the side with the Mk V).

Trivia

 * A Crystal Chip is seen on some of the Cafeteria tables on the Pillar of Autumn