Research On Performance And Infrastructure Of TrueFFS File System

With the rapid development of electronic technologies, Flash memory was applied widely for its good characters,such as small size, low power consumption, storage capacity and non-volatile,and it was used to more and more fields,including aerospace, communications, transportation and so on. How to provide an efficient file system to improve the perfomance of Flash,and to extend the life time has become a hot topic now.TrueFFS is the M-system designed for VxWorks real-time operating system.It provides a common device interface for the majority of Flash storage, so the designers do not have to care about the difference between Flash and the general disk.TrueFFS has greatly simplified the operation process.At the same time, it has reentrant,thread-safety features,has been successfully used in aerospace,military and other areas.The main work that we achieved includes:(1)We introduce the system architecture and key technologies of TrueFFS and do lot of research on the data structure ,operation process,Flash Translation Layer.Then,we point out the strengths and weaknesses of TrueFFS.(2)In this paper,a Flash translation layer called TFTL and a garbage collection scheme called partial block clean is introduced.TFTL provides an abstraction of a block based device which provides strict guarantees for reads and writes.The service guarantees are close to an ideal theoretical case.Partial block clean provides a constant time memory allocator for Flash. With these improvements, making TrueFFS greatly improved.(3)After do the research on the Wear-Leving of TrueFFS,we proposed a Wear-Leving mechanism that moving data which are not update so often.It distributes Weat-Leving actions over the entire physical address space, so that static or rarely updated data can be proactively moved and memory-space requirements can be minimized.The lifetime of the Flash which used TrueFFS can be extended.