  We present ROSfs, a novel user-level file system for the Robot Operating
System (ROS). ROSfs interprets a robot file as a group of sub-files, with each
having a distinct label. ROSfs applies a time index structure to enhance the
flexible data query while the data file is under modification. It provides
multi-robot systems (MRS) with prompt cross-robot data acquisition and
collaboration. We implemented a ROSfs prototype and integrated it into a
mainstream ROS platform. We then applied and evaluated ROSfs on real-world UAVs
and data servers. Evaluation results show that compared with traditional ROS
storage methods, ROSfs improves the offline query performance by up to 129x and
reduces inter-robot online data query latency under a wireless network by up to
7x.
