Weed-FS is a simple and highly scalable distributed file system. There are two objectives: to store billions of files, and to serve the files fast! Instead of supporting full POSIX file system semantics, it implements only a key-file mapping. Instead of managing all file metadata in a central master, it manages file volumes in the central master and lets volume servers manage files and the metadata. This relieves concurrency pressure from the central master and spreads file metadata into volume servers' memories, allowing faster file access with just one disk read operation. It is modelled on Facebook's Haystack design paper. Only 40 bytes of disk storage are required for each file's metadata, and disk reads are O(1).
Fubsy is a tool for efficiently building software. In concrete terms, it lets you conditionally (re)build targets from sources based on which sources have changed since the last build. Typically, targets and sources are all files in a directory tree. In theory, they can be any resource on a computer. More abstractly, Fubsy is an engine for conditional execution of actions based on the dependencies between related resources.