Like other supercomputers, Sierra was girthy. She was composed of thousands of compute nodes, stored one on top of another in racks—basically cabinets—that held up her processing innards. She had 240 of these racks, spread across roughly 7,000 square feet. All of this was needed to support her life’s main occupation: performing specialized, super-high-security simulations for the National Nuclear Security Administration. At the time of her death sentence, her processing power ranked a still-respectable 23rd in the world.