In this paper we present a design and architecture for a concurrent file system server. This architecture is a compromise between the fully concurrent V6 UNIX implementation, and the simple sequential implementation in the MINIX operating system. The design of the server is made easier through the use of a disciplined model of concurrency, based on the CSP process algebra. By viewing the problem through this restricted lens, without traditional explicit locking mechanisms, we can construct the system as a process network of components with explicit connections and dependencies. This provides us with insight into the problem domain, and allows us to analyse the issues present in concurrent file system implementation.