A Research Unix Reader says: Sandy (A. G.) Fraser devised the Spider local-area ring (v6) and the Datakit switch (v7) that have served in the lab for over a decade. Special services on Spider included a central network file store, nfs, and a communication package, ufs. Datakit, a “central office” for data communication, gave added impetus to research in distributed computing. Fraser undertook the Unix Circuit Design System (see CDL in section 4.3) to support his hardware projects.