| Advances in the performance of commodity hardware and acceptance of open-source software have recently led to the increased use of systems based upon a combination thereof as network appliances. The principal thesis of this dissertation is that such appliances can operate more efficiently if their operating system is designed specifically for that task. I present Piglet as a novel design for such an operating system, and describe its implementation and evaluation in such a context.; The core of the Piglet architecture is the Active Kernel. A dedicated kernel processor provides concurrency between kernel and applications and enables asynchronous shared-memory communication. The use of shared objects for all communication between applications and the kernel permits Piglet to offer much more efficient mechanisms for the invocation of system services than a conventional kernel.; The experimental results presented herein demonstrate how these fundamental kernel features make Piglet a more efficient operating system for network appliances: reduced latency for individual operations and increased aggregate data throughput. In addition to detailing microbenchmark results to support those claims, I show how an existing web server application can readily make use of those enhancements to achieve a performance boost over standard operating systems.; Finally, this dissertation examines, both quantitatively and qualitatively, some of the challenges and problems presented by the implementation of the Piglet architecture, and proposes solutions and/or architectural changes to address those concerns. |
