Sierra supercomputer decommissioned and cooled with recirculation system. Shutdown involved phased rotor node removal and watertight safety procedures.
San Francisco: Supercomputers are rated by how fast they do math problems called floating-point operations. One at a time math is slow, but billions at a time are fast. Sierra could do 94.64 quadrillion floating-point operations in one second. That’s why it was a supercomputer.
The lab workers announced to the scientists that Sierra would be shut down. No one could start new jobs on Sierra. The workers disconnected parts one by one. First they removed compute parts that did the math. Last they removed the parts that told everything what to do. This process took many careful steps.
The workers ran script programs that told Sierra to stop. Then they used a physical switch to cut power. They also drained thousands of gallons of water that kept Sierra from overheating. Water came through pipes under floor and was very hot. Safety workers tested water before releasing it to be sure it would not hurt the environment.