The Stone Soupercomputer was a Beowulf-style computer cluster built at the US Oak Ridge National Laboratory in the late 1990s.
A group of lab employees including William W. Hargrove and Forrest M. Hoffman applied for a grant to build a cluster in 1996, but it was rejected.
They decided to build a cluster anyway, using desktop personal computers that had been discarded as being too slow.
[1] The developers used freely available and open source software such as Linux operating system, the Parallel Virtual Machine toolkit, and the Message Passing Interface library.
They included Intel 80486 and Pentium-based machines as well as a few DEC Alpha workstations.