Comment by quicklime

> When a car goes around a turn, more ground must be covered by the outside wheels; likewise, the outer edge of a spinning hard disk moves faster than the inner one. Google had moved the most frequently accessed data to the outside, so that bits could flow faster under the read-head, but had left the inner half empty; Jeff and Sanjay used the space to store preprocessed data for common search queries

So Google was a company that was too cheap to buy ECC RAM, but willing to let half of their hard disks go to waste. I'm struggling to understand the logic behind this; can anyone explain?