TESTING RELATED: Why we need testing, Fault analysis system, JTAG, TAP Controller, BIST, types of fault, what will happen if we put nmos up and pmos down in an inverter, black box white box testing, MTTF, failure rate over product lifetime, what is D algorithm, stuck at fault, stuck open fault, stuck sort, SCAN, delay fault models, check point theorem, how to know that a primary input can be detected by what test patterns for respective stuck at faults, what happenes with XOR gate, what is level-based-analysis, what is structural and non-structural testing, why we need structural testing, testability, observability, controlability, what is level based logic simulation and why we need it? critical path tracing... etc HR Question: some 3 bulbs question he asked, there are 2 rooms, one room has 3 bulbs and another has all three switches. in just one go you need to find out which switch belongs to which bulb?