In a paper titled "Cores that don’t count" [PDF], Hochschild and colleagues Paul Turner, Jeffrey Mogul, Rama Govindaraju, Parthasarathy Ranganathan, David Culler, and Amin Vahdat cite several plausible reasons why the unreliability of computer cores is only now receiving attention, including larger server fleets that make rare problems more visible, increased attention to overall reliability, and software development improvements that reduce the rate of software bugs. "But we believe there is a more fundamental cause: ever-smaller feature sizes that push closer to the limits of CMOS scaling, coupled with ever-increasing complexity in architectural design," the researchers state, noting that existing verification methods are ill-suited for spotting flaws that occur sporadically or as a result of physical deterioration after deployment.