Behavior-Driven Testing of Windows Device Drivers

Commercial-off-the-shelf operating systems (COTS OSs) increasingly favor adaptability to support diverse application and hardware peripherals in detriment to targeting robustness of OS services. The COTS OSs interface to hardware devices is provided by the device-drivers1. Furthermore, drivers have themselves become add-on COTS components, enhancing OS’s adaptability. Unfortunately, drivers constitute a prominent cause of computer system outages, impacting overall service reliability [5]. We note at least two facts that might explain why the drivers are the weak link in a computer system equipped with a COTS OS. First, drivers are relatively immature pieces of software, exhibiting a higher defect density compared with the OS kernel. One reason is that many hardware producers are forced by fierce competition to push their new peripherals onto the market before they could be tested properly. Additionally, the set of loaded drivers is likely to be different across installations. The difficulty to define all the interactions with other drivers or parts of the system significantly reduces the effectiveness of design-stage driver testing. Therefore, assessing continuous service provision in different environments and system configurations is still a difficult problem to solve.