On page 3 of the Research Unix reader (http://www.cs.dartmouth.edu/~doug/reader.pdf) "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." I do not recall ever seeing any SPIDER related code in the public V6 source tree. Was it ever released outside Bell Labs? From a bit of Googling I understand that SPIDER was a ATDM ring network with a supervisor allocating virtual circuits. Apparently there was only ever one SPIDER loop with 11 hosts connected, although Fraser reportedly intended to create multiple connected loops as part of his research. The papers that Fraser wrote are hard to find: lots of citations, but no copies, not even behind pay walls. The base report seems to be: A. G. FRASER, " SPIDER-a data communication experiment", Tech Report 23 , Bell Lab, 1974. Is that tech report available online somewhere? Tanks! Paul