Dawning 2000 Single System Image File System Cosmos Operating System Design And Realization Of The Relevant Layer

COSMOS File System is a Single-System-Image File System running on Dawning 2000 System that is a workstation cluster.COSMOS provides users a single system image that the cluster seems a single computer to users. The boundary of the SSI is the sharing portion of the file system, that is to say, the mounted file system which type is cosmos (just as ufs, nfs). COSMOS implements multiple-read single-write token mechanism in order to maintain single image of data in the file system.COSMOS also implements serverless model in order to improve the scalability of the system. Study in some other network file system indicates that scalability of system is always restricted by server in traditional centralized client/server model. So we use serverless model mechanism.COSMOS File System implements VFS/Vnode Interface and runs as extension of OS Kernel. Access of data in COSMOS is implemented by passing System Calls to Vnode Operations in COSMOS File System via Logical File System Layer. No further information is needed. So COSMOS implements transpency and binary compatibility to applicaion for a single computer.Data in COSMOS File System are stored in many disks in one of Storage Stripes and are accessed parallelly. COSMOS implements multi-read single-write token management mechanism and Cooperative Cache policy, Greedy Forwarding.Based on study of some file systems, this thesis draws the design plan of COSMOS File System, discusses over some crucial problems in implement, and gives the performance result of prototype.