What was found
(CAN) MULTIPLE RED, AMBER WARNING AND CAUTION MESSAGES: GRNG PROX WARNING, AIR DATA INERTIAL REFERENCE, INERTIAL REFERENCE INDICATORS AND NAV & PRIMARY FLIGHT DISPLAYS, WENT BLANK, NUMEROUS RED OVERSPEED WARNINGS, SLAT FLAP, AND FLIGHT CONTROL MESSAGES. ALL OCCURED WITH AIRCRAFT ON GROUND WHILE WAITING FOR TAKE-OFF. AIRCRAFT RETURNED TO GATE.AIRDATA / INERTIAL REFERENCE UNIT REPLACED AS PER AMM 34-12-34-420-050 SYSTEM CHECKED SERVICEABLE