Robert Martin of the Mitre Corporation says that testing large systems may not be possible.
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In many cases, it may be next to impossible to prove that the Y2K problem has been fixed. One reason is that many systems interface with components that cannot be rolled forward to test. Satellite networks and telephone systems are two examples. These interfaces can be simulated and analyzed, but it may not be possible to test them to the same level of confidence as other systems. The need to work with users should not be overlooked. They need help to understand the levels and types of risk the system has so they will remain confident in the system's performance.