Device Driver Reliability

Abstract

Despite decades of research in extensible operating system technology, extensions such as device drivers remain a significant cause of system failures. In Windows XP, for example, drivers account for 85% of recently reported failures. This chapter presents Nooks, a layered architecture for tolerating the failure of drivers within existing operating system kernels. The design consists techniques for isolating drivers from the kernel and for recovering from their failure. Nooks isolates drivers from the kernel in a lightweight kernel protection domain, a new protection mechanism. By executing drivers within a domain, the kernel is protected from their failure and cannot be corrupted. Shadow drivers recover from device driver failures. Based on a replica of the driver’s state machine, a shadow driver conceals the driver’s failure from applications and restores the driver’s internal state to a point where it can process requests as if it had never failed. Thus, the entire failure and recovery is transparent to applications.