RAPID-Transit was a testbed for experimenting with caching and prefetching algorithms in parallel file systems (RAPID means “Read-Ahead for Parallel Independent Disks”), and was part of the larger NUMAtic project at Duke University. The testbed ran on Duke’s 64-processor Butterfly GP1000. The model we used had a disk attached to every processor, and that each file was striped across all disks. Of course, Duke’s GP1000 had only one real disk, so our testbed simulated its disks. The implementation and some of the policies were dependent on the shared-memory nature of the machine; for example, there was a single shared file cache accessible to all processors. We found several policies that were successful at prefetching in a variety of parallel file-access patterns.