databank
900 year diary
index file
Part of the TARDIS databank, which Tegan Jovanka and Nyssa referred to in an attempt to stop themselves being destroyed in Event One. By using it, Tegan piloted the TARDIS to the planet Castrovalva, where the Master had set a trap for the newly regenerated Doctor. Later, on returning to the TARDIS, the Doctor explained that much of the information Tegan used in the Index File was false, placed there by the Master as part of the trap. This false information included her ability to fly the Ship, which was actually on a course preprogrammed by a Block Transfer Computation duplicate of Adric.