What is needed is a rigorous test similar to Plantinga's that looks critically at the hardware and software of a system to see if it indeed is providing warrantable information. There is a high statistical probability that the information produced under these conditions will be true. Criterion one addresses proper function and environment. Proper function is almost too obvious to mention, except that we have Pentium processors in machines across the nation and we know that these are defective. Yet we use them daily.
Proper function is testable.
A sensor that sends inaccurate data cannot be a basis for warrant. A program that intermittently drops or garbles bits of data cannot provide a basis for understanding the objective reality it is designed to monitor. But functional testing must be done in the real world environment in which the system will operate. A sensor designed to measure atmospheric phenomena on Earth may or may not give valid data when sent to Venus. In either case, its data could not be a basis for warranted belief without some additional test that demonstrates proper function in a Venusian atmosphere.