What is a Beowulf cluster? Jacek and Douglas give a good definition in their article: "Beowulf is a multi-computer architecture which can be used for parallel computations. It is a system which usually consists of one server node, and one or more client nodes connected together via Ethernet or some other network". The site beowulf.org lists many web pages about Beowulf systems built by individuals and organizations. From these two links, one can be exposed to a large number of perspectives on the Beowulf architecture, and draw his / her own conclusions.
What’s the difference between a true Beowulf cluster and a COW [cluster of workstations]? Brahma gives a good definition: http://www.phy.duke.edu/brahma/beowulf_book/node62.html.
If you are a “user” at your organization, and you have the use of some nodes, you may still do the instructions shown here to create a cow. But if you “own” the nodes, that is, if you have complete control of them, and are able to completely erase and rebuild them, you may create a true Beowulf cluster.
In Brahma's web page, he suggests you manually configure each box, and then later on (after you get the feel of doing this whole “wolfing up” procedure), you can set up new nodes automatically (which I will describe in a later document).