Finding and fixing design bugs in computer chips after they've been fabricated in silicon can be a tedious and costly process due to signals being buried inside the silicone. Engineering researchers at the University of Michigan have developed a new technology called FogClear to automate post-silicon debugging. FogClear uses puzzle-solving search algorithms to diagnose problems early on and automatically adjust the blueprint for the chip. It reduces parts of the process from days to hours.
In the current system, a chip design is validated in simulations and then a draft is cast in silicon. This first prototype undergoes additional verification. If a bug is detected at this stage, an engineer must craft a fix that does not disrupt the balance of the system's other components, which could take days. Engineers then produce new prototypes incorporating all the fixes. This process repeats until they arrive at a bug-free prototype.
FogClear automates this debugging process. The computer-aided design tool can catch subtle errors that months of simulations would still miss. Some bugs might take days or weeks before causing any miscomputation, and they might only do so under very rare circumstances. The new application searches for and finds the simplest way to fix a bug - the one that has the least impact on the working parts of the chip. The solution usually requires reconnecting certain wires, and does not affect transistors.