Like anyone who has anything to do with the business of running applications attached to the Internet, I can’t help but feel uneasy and stressed when an outage as severe and impacting as the one Amazon Elastic Block Store has just experienced happens. The fact that Amazon is a competitor doesn’t matter. It just sucks for everyone. This post, however, isn’t about EBS. Not really. It’s about abstractions. In particular, the abstraction of “the disk.