In February 1994, using four of the 486DX2 66MHz systems that Intel had donated to Purdue for the undergraduate logic design and OS courses, we built the world's first parallel-processing Linux PC cluster. The PCs were connected by both Ethernet and our custom PAPERS hardware.
This cluster was regularly assembled and disassembled working around the lab class schedule. We stopped using it in late 1994.
The only thing set in stone is our name.