From WikiChip

The term Supercomputer usually defines a large system comprised of a huge number of individual systems. In the past(1970s-1990s) a Supercomputer was a indivudual, custom cpu(core), due to lacking connectivity and the rising major cpu providers having datacenters as their main business. Today, Supercomputers usually run a custom flavor of Linux, and each node is connected to high-speed, low-latency InfiniBand switches which handle job sharing and connecting specialized nodes to generally used nodes, like storage.