The ADIRUs(Air Data Inertial Reference Unit) provide information such as Altitude, Airspeed and other air data information as well as inertial position which is an independant navigation position for the aircraft, search for inertial navigation on the net and you'll get an idea about what its all about. There are three ADIRUs on this type of aircraft.
The ISIS(Integrated Standby Instrument System) is electronic version of the back up instruments. It contains all the required sensing elements in a single unit to provide similar information to the ADIRUs
Prim 1 is one of the primary flight control computers of which there are three.
Sec 1 is one of the secondary flight control computers of which there are two. These are brains behind the flight control system. There are three laws for the FBW system and these are Normal Law, Alternate Law and Direct Law.