A communication mechanism for resource isolation

Sharing resources between multiple untrusted clients requires a shared service that provides access to the resources upon client requests. But executing these requests needs other resources, like memory or CPU time, which must be carefully allocated. In this paper, we investigate a communication mechanism that allows access to shared services without changing existing allocation decisions. This is achieved by systematically using the new resource lending principle, that allows a service to use the resources of its clients to perform the request. We present an easily understandable design model for this communication mechanism named the thread lending model, that completely avoids any allocation by the service, and demonstrate its implementation in our prototype OS Anaxagoros. We finally investigate the consequences of using this model on the structure and implementation of the shared services.