Efficient and predictable high-speed storage access for real-time embedded systems

As the speed, size, reliability and power efficiency of non-volatile storage media increases, and the data demands of many application domains grow, operating systems are being put under escalating pressure to provide high-speed access to storage. Traditional models of storage access assume devices to be slow, expecting plenty of slack time in which to process data between requests being serviced, and that all significant variations in timing will be down to the storage device itself. Modern high-speed storage devices break this assumption, causing storage applications to become processor-bound, rather than I/O-bound, in an increasing number of situations. This is especially an issue in real-time embedded systems, where limited processing resources and strict timing and predictability requirements amplify any issues caused by the complexity of the software storage stack. This thesis explores the issues related to accessing high-speed storage from real-time embedded systems, providing a thorough analysis of storage operations based on metrics relevant to the area. From this analysis, a number of alternative storage architectures are proposed and explored, showing that a simpler, more direct path from applications to storage can have a positive impact on efficiency and predictability in such systems.