"It's incredibly redundant."
Dr. Radek Zelenka on the database's ability to back up data[src]

The Atlantis database also known as the Ancient database is the central computer database containing the knowledge the Ancients gained up to when they left Atlantis. The database can be accessed anywhere in the city, but the holo room is the best place to start for first-time users. The room is known to take a toll on power relative to the terminals and the power of a Naquadah generator, however, so the Atlantis expedition uses it sparingly. Ganos Lal devised a teaching program to instruct younger Lanteans using the information in the database. (SG1: "The Pegasus Project", SGA: "Rising", "The Siege, Part 2")

The exact size of the database relative to Earth data storage is unknown. Dr. McKay devised an advanced compression program to allow optimal data storage. However, given the limited amount of drives available at the time, Radek believed less than 10% of the portion they had deciphered at that point could be taken with them, had they evacuated. (SGA: "The Siege, Part 1")

Known information stored in the database includes:

Community content is available under CC-BY-SA unless otherwise noted.