Allen School alumna Irene Zhang (Ph.D., ’17) has been recognized with the 2018 Dennis M. Ritchie Doctoral Dissertation Award at the 13th USENIX Symposium on Operating Systems Design and Implementation (OSDI) taking place in Carlsbad, California. The award committee selected Zhang’s dissertation, “Towards a Flexible, High–Performance Operating System for Mobile/Cloud Applications,” for its breadth and potential to inspire future research.
Zhang’s thesis makes multiple contributions spanning mobile and cloud computing. Today’s applications have become incredibly difficult to write; no longer simple desktop programs, they are now surprisingly complex distributed systems with components spread across geographically and functionally diverse mobile devices and cloud servers. Zhang presents multiple systems that address the challenges of programming in this space.
The first of Zhang’s contributions, Sapphire, offers both a new methodology for writing distributed applications and a system supporting that methodology. The Sapphire system greatly simplifies programming for distributed applications by separating generic application logic from distributed deployment decisions, such as where data or computation should be located, what data should be cached or replicated, and what consistency guarantees are necessary.
Another system, named Diamond, is concerned with a relatively new property of modern applications: reactivity. Applications such as games and social networking expect changes to distributed state to be propagated automatically and instantly to other users and to durable storage, so that all users see the same values in the same order. With Diamond, changes to shared application variables on any device automatically cause those values to be made durable in the cloud, update the values on other devices sharing them, and trigger those devices to “react” to the changes by updating the user interface so the user quickly sees the change.
Finally, in TAPIR (“Transactional Application Protocol for Inconsistent Replication”), Zhang dissects the protocols used in today’s distributed storage systems to improve the performance of consistency management among replicas. By simplifying the replication protocol with a technique she calls “inconsistent replication,” Zhang is able to provide both lower latency and higher throughput on distributed storage systems without sacrificing transactional properties.
The Dennis M. Ritchie Award was created by the Association for Computing Machinery’s Special Interest Group in Operating Systems (ACM SIGOPS) to recognize and encourage creative research in software systems in honor of A. M. Turing Award winner Dennis Ritchie, who was a pioneer in operating systems theory and implementation of the UNIX operating system. The award is presented during alternating years at OSDI and the ACM Symposium on Operating Systems (SOSP).
Zhang, who earned her Ph.D. working with professors Arvind Krishnamurthy and Hank Levy and is now a researcher at Microsoft Research, is the second Allen School student to be acknowledged by the Ritchie Award. Alumna Roxana Geambasu (Ph.D., ’11) earned an Honorable Mention for her dissertation “Empowering Users with Control over Cloud and Mobile Data” in 2013, the first year in which the award was given.