I'm currently involved in several research projects at CMU:

PASIS: I am involved in the design and implementation of the PASIS R/W (providing read/write access) and Q/U (providing general replicated state machines semantics) protocols. The protocols are scalable, Byzantine fault-tolerant, optimistic, versatile, and use quorums to achieve scalability. One of the key features of the protocols is the use of versioning storage: servers do not overwrite data on a write operation but instead create a new version.

Self-* Storage: The administrative cost in today's storage systems is a growing problem. We are investigating how to alleviate this burden through self-{configuring, healing, organizing, managing, tuning} systems, constructed using commodity storage bricks. I am involved in several aspects of the Self-* storage project: distributed data access protocols (using the PASIS read/write protocol), garbage collection, and an NFS server.

End System Multicast: Overlay multicast is an architecture for implementing multicast without relying on multicast support in routers. The end systems self-organize into an overlay tree and dynamically optimize the tree based on current network conditions. However, in some broadcasts, the end systems may lack the necessary resources (e.g., most hosts may have limited upstream bandwidth). I was involved in the design and implementation of a waypoint system for ESM; waypoints are hosts uninterested in the actual broadcast but which are added to provide resources. Our system is on-demand (waypoints are added only when resources are low, and are removed when they are no longer required), location-aware (we use waypoints that are close to the bandwidth-lacking region), and self-monitoring (unhelpful waypoints are removed from the system).


During my undergraduate years at the University of Waterloo, I was involved in an autonomous aerial robotics student project. As well, I built a Java XML serialization library and investigated proxy servers and compression during two research assistantships. Waterloo has a great co-op program, and I had the fortune of interning at Sun Labs in sunny California four times. While at Sun Labs, I implemented a checkpointing facility for the HotSpot Java virtual machine, and ported the optimizing compiler of the Self virtual machine from SPARC to PowerPC.