A Study Of File System Based On Exokernel Operating System

The responsibility of the operating system abstracts computer hardware and provides the interface between applications and hardware resources. Traditional file system on operating system hides specific file management strategy in kernel so that applications cannot determine the distribution of data blocks on the disk though they know how to manage their own data. This strategy limits performance and reliability of the applications. Exokernel is more simplified and it separates the resources management from resources protection. Exokernel is responsible for hardware resources protecting while applications can manage hardware resources. Applications have the ability to directly manipulate hardware according to their own data access so exokernel meets the requirements of application performance. The work in this thesis is to implement file system in user space based on prototype of exokernel operating system to handle the other user process requests of accessing disk.This thesis implements the key mechanisms for file system dependence, which include User Exception, Inter-Process Communication(IPC) and Privilege Process Access. Process is able to handle exceptions with User Exception so as to make process more robuster. IPC provides a way to transfer integer value or memory pages. User process can request disk data from file system process with IPC. Privilege Process Access has the ability to access disk directly.The implementation of file system is another job in this thesis including data structure designing, syscall designing, disk driver and IPC protocol based on these key mechanisms. User can operate the data on the disk with IPC protocol. Finally, there is validation for correctness of the file system and benchmark the performance of file system on exokernel operating system prototype including sequential access and random access.