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@(#)abstract.ms 5.2 (Berkeley) 04/16/91
Toward a Compatible Filesystem Interface .AU Michael J. Karels Marshall Kirk McKusick .AI Computer Systems Research Group Computer Science Division Department of Electrical Engineering and Computer Science University of California, Berkeley Berkeley, California 94720
As network or remote filesystems have been implemented for X , several stylized interfaces between the filesystem implementation and the rest of the kernel have been developed. Notable among these are Sun Microsystems' virtual filesystem interface using vnodes, Digital Equipment's Generic File System architecture, and AT&T's File System Switch. Each design attempts to isolate filesystem-dependent details below the generic interface and to provide a framework within which new filesystems may be incorporated. However, each of these interfaces is different from and incompatible with the others. Each of them addresses somewhat different design goals. Each was based upon a different starting version of X , targetted a different set of filesystems with varying characteristics, and uses a different set of primitive operations provided by the filesystem. The current study compares the various filesystem interfaces. Criteria for comparison include generality, completeness, robustness, efficiency and esthetics. As a result of this comparison, a proposal for a new filesystem interface is advanced that includes the best features of the existing implementations. The proposal adopts the calling convention for name lookup introduced in 4.3BSD. A prototype implementation is described. This proposal and the rationale underlying its development have been presented to major software vendors as an early step toward convergence upon a compatible filesystem interface.