A computer terminal with primary, secondary, and auxiliary systems data
A primary system was an important and vital computer system aboard a starship.
When Enterprise NX-01 arrived at the location of the Earth Cargo Service freighter ECS Fortunate, Malcolm Reed detected hull damage, an offline warp reactor, and most of the primary systems down aboard the Fortunate. (ENT: "Fortunate Son")
The computer terminal in the ship's pantry featured data of the primary, secondary, and auxiliary systems aboard the ship. (ENT: "The Catwalk")
According to Commander Tucker, the Borg modified the primary systems aboard the Arctic One-type transport Arctic One including engines and hull plating. (ENT: "Regeneration")