Dennis joined Microsoft Research's Silicon Valley lab in May, 2003 and was a Researcher there when the lab was closed in September, 2014. Before that, he had worked at the Systems Research Center, which was absorbed into HP Labs, and the Center for Coastal Studies, which was part of the Scripps Institution of Oceanography at UC San Diego.

His research interests are currently focused around distributed systems and information retrieval. Interesting projects in the area of data and compute intensive distributed computing include Dandelion, a project to enable users to program a cluster of heterogeneous systems via a high level language; Dryad, a distributed execution engine for distributed data-parallel programs; DryadLINQ, a project to enable users to write large scale distributed applications in a high-level language; and TidyFS, a distributed filesystem designed for data-parallel workloads. In the area of Information Retrieval and Web Search, notable projects include PageTurner, a large scale study of the evolution of web-pages; the MSRBot web crawler, a distributed web crawler used within Microsoft as well as licensed externally; and a project evaluating policies for corpus selection.

More information, including a publication list, is available from his Google Scholar profile, his full resume/CV, or his LinkedIn profile. He can be contacted by email at his first name [at] his last name [dot org].