FiST: A Language for Stackable File Systems

Erez Zadok, Jason Nieh

Proceedings of the 2000 USENIX Annual Technical Conference, San Diego, CA, June 18-23, 2000, pp. 55-70


Traditional file system development is difficult. Stack- able file systems promise to ease the development of file systems by offering a mechanism for incremental develop- ment. Unfortunately, existing methods often require writ- ing complex low-level kernel code that is specific to a sin- gle operating system platform and also difficult to port. We propose a new language, FiST, to describe stackable file systems. FiST uses operations common to file system interfaces. From a single description, FiST’s compiler pro- duces file system modules for multiple platforms. The gen- erated code handles many kernel details, freeing developers to concentrate on the main issues of their file systems. This paper describes the design, implementation, and evaluation of FiST. We extended file system functionality in a portable way without changing existing kernels. We built several file systems using FiST on Solaris, FreeBSD, and Linux. Our experiences with these examples shows the following benefits of FiST: average code size over other stackable file systems is reduced ten times; average devel- opment time is reduced seven times; performance overhead of stacking is 1–2%.



Columbia University Department of Computer Science