CRFS

CRFS is a user-space filesystem that mounts container images directly from remote registries, exposing them as ordinary directories without a full “pull” step. Instead of downloading entire layers upfront, it fetches file ranges on demand and maintains a content-addressed cache, yielding fast startup and lower bandwidth for large images. The system speaks registry protocols and understands layered image formats, resolving whiteouts and overlays so the mounted view matches what a container runtime would see. A FUSE (or platform-equivalent) frontend makes it trivial to integrate with existing tools: compilers, test runners, or debuggers can read files as if they were local. This lazy, verified access pattern is especially valuable in CI and developer workflows where you inspect or compile a few files from a massive base image. By treating registries as a read-only filesystem, CRFS turns image artifacts into first-class, quickly accessible build inputs.