Just as I shudder thinking about some of the cars my family owned in the 1970s, requiring an inter-service station map to plot our gas-guzzling course, I'm sure our children will bristle at the notion of rooms full of chillers that use as much power as the equipment they're cooling. The solution is to generate less heat -- cooler CPUs, better system packaging, and even improved inter-chip communications like the Proximity I/O work in Sun Labs that reduces energy consumption (and therefore heat) at a systems level. Whenever we think of some resources -- oil or cooling capacity -- as infinite, we design badly. When they're constraints, we drive responsibility. I still worry that Tannenbaum's station wagon full of tapes only gets 4 miles to the gallon.