In traditional computing, a node is an object on a network. For example, on a home network, your computer, router, and printer might all be nodes. Supercomputers like Kraken are essentially networks, with nodes that communicate with each other to solve a larger problem than any singular computer could in a reasonable amount of time. Kraken contains several types of nodes; compute nodes are the work-horses of the system, and are much like a stripped-down computer. An I/O node is the interface between the compute nodes and other computers, that is, it deals with input and output for the system.