Fixing Bugs in Hardware
Software diagnoses problems in chip prototypes and offers fast, cheap solutions
Source: “Automatic Post-Silicon Debugging and Repair”
Valeria Bertacco et al.
International Conference on Computer-Aided Design, November 6, 2007, San Jose, CA
Results: Researchers at the University of Michigan have developed software that finds flaws in computer chips and proposes economical fixes. The software is able to repair about 70 percent of bugs.
Why it matters: Before a chip is mass-produced, a prototype is shipped from the fabrication facility to the chip designers for testing. Currently, engineers can spend up to a year manually inspecting a prototype for mistakes, such as design errors, misplaced transistors, or wires that are too close together. Each time flaws are identified and corrected, a new prototype has to be made and tested. Each iteration can cost millions of dollars, and repeated prototyping delays commercialization. Manual bug-hunting is also prone to error and may result in products with faults that can be exploited by computer viruses.
Methods: Engineers test chip prototypes by hooking them up to probes that send electrical stimuli through them and record the output. The Michigan researchers wrote software that quickly runs through thousands of input signals and analyzes the output, zeroing in on problem areas. Likewise, it identifies ways to fix bugs by running through a series of simulations to find a design variation that offers the fastest and most cost-effective solution, one that may not be obvious to an engineer looking at a wiring diagram.
Next steps: The researchers are looking into some of the debugging challenges specific to multicore processors–chips with more than one processing center.