FAULT-TOLERANT COMPUTER STUDY FOR SAFETY-CRITICAL SYSTEMS

AS A MINIMUM, NUCLEAR SAFETY CROSS-CHECK ANALYSIS (NCCCA) REQUIRES POSITIVE MEASURES TO PREVENT WEAPON YIELDS DUE TO ACCIDENTS OR INCIDENTS; PREVENT DELIBERATE ARMING, LAUNCHING, FIRING, OR RELEASING WEAPONS EXCEPT UNDER EMERGENCY WAR ORDERS FROM COMPETENT AUTHORITY; PREVENT INADVERTENT ARMING, LAUNCHING, OR RELEASING OF NUCLEAR WEAPONS; AND ENSURE ADEQUATE SECURITY OF NUCLEAR WEAPONS. WHEN COMPUTERS ARE USED IN SAFETY-CRITICAL APPLICATIONS IT BECOMES NECESSARY TO ENSURE THAT ALL CREDIBLE FAULTS DO NOT INVALIDATE THE SAFETY DESIGN. THE USE OF REDUNDANT CIRCUITRY, IF PROPERLY IMPLEMENTED, WILL ENABLE THE USE OF COMPUTERS WHERE ULTRA HIGH SAFETY AND RELIABILITY IS NEEDED. FAIL-SAFE TECHNOLOGY PROPOSES A SIX-MONTH STUDY THAT WILL ESTABLISH DESIGN BOUNDARIES AND OPTIONS FOR IMPLEMENTING SAFETYCRITICAL SYSTEMS.