Dynamic service reconfiguration and migration in the Kea kernel

Kea is a new operating system developed for experimentation with kernel structuring, configuration and specialization. There are several features of Kea´s design that make the investigation of these issues practical. Firstly it supports fine-grain decomposition of kernel services, the components of which communicate using inter-domain calls. This communication mechanism forms the backbone of Kea´s reconfigurability, as services can be located in separate domains, for development or debugging purposes, and then dynamically migrated into a common domain, or into the kernel itself, transparently to the users of the service. The inter-domain calls are automatically optimized to procedure calls as appropriate. The service hierarchy can also be dynamically reconfigured through replacement, or the layering of new services, either on a system wide or application specific basis. We describe these features, and discuss the results from several experiments that demonstrate the practicality and performance advantages of Kea´s design