They did, in 2007. Things might have changed by now.<p><a href="https:&#x2F;&#x2F;static.googleusercontent.com&#x2F;media&#x2F;research.google.com&#x2F;en&#x2F;&#x2F;archive&#x2F;disk_failures.pdf" rel="nofollow">https:&#x2F;&#x2F;static.googleusercontent.com&#x2F;media&#x2F;research.google.c...</a>