Abstract
This paper describes a file system for supporting quality of service (QoS) guarantees. The device driver model clearly separates control- and data-path operations and presents a low-level of abstraction. The data-path module provides translation and protection of I/O requests enabling the file system layers to be executed as unprivileged code within shared libraries. Scheduling of low-level operations within the device driver is used to provide isolation between clients and quality of service guarantees.