The existence of two basic levels of storage (fast/volatile and slow/non-volatile) has been a long-standing premise of most computer systems, influencing the design of OS components, including file systems, virtual memory, scheduling, execution models, and even their APIs. Emerging resistive memory technologies – such as phase-change memory (PCM) and memristors – have the potential to provide large, fast, non-volatile memory systems, changing the assumptions that motivated the design of current operating systems.

The architecture research community is actively exploring the implications of fast, cheap non-volatile memory, including error correction mechanisms and memory hierarchy organization. Software research has focused primarily on NVRAM-based file systems that maintain current file system semantics and on programming interfaces for persistent objects. These efforts are evolutionary: they integrate NVRAM into existing architectures and programming structures.

Instead, we believe that NVRAM could be revolutionary rather than evolutionary; this project seeks to explore the ways that cheap byte-addressable NVRAM could substantially affect OS design. We seek to answer the question: What if future systems contained only one level of memory that was persistent and uniform? What if there were no disk pages, no memory pages, no buffer cache, no page faults, no swapping, no booting on restart? We are currently designing a single-level storage system and key-value store focusing on the problems of (1) organization and structure (2) sharing and protection and (3) new features or simplifications exposed by this technology.

Current Contacts: Katelin Bailey, Peter Hornyack, Luis Ceze, Steve Gribble, and Hank Levy.

Publications

Operating System Implications of Fast, Cheap, Non-Volatile Memory (HotOS 2011), Katelin Bailey, Luis Ceze, Steven D. Gribble, Henry M. Levy.