The topic of data storage is one that does not need to be well understood until something goes wrong (data disappears) or something goes really right (too many customers). Because databases can be treated as black boxes with an API, their inner workings are often overlooked. They are often treated as magic things that just take data when offered and supply it when asked. Since these two operations are the only understood activities of the technology, they are often the only features presented when comparing different technologies. Benchmarks are often provided in operations per second, but what exactly is an operation? Within the realm of databases, this could mean any number of things. Is that operation a transaction? Is it an indexing of data? A retrieval from an index? Does it store the data to a durable medium such as a hard disk, or does it beam it by laser toward Alpha Centauri? It is this ambiguity that causes havoc in the software industry. Misunderstanding the features and guarantees of a database system can cause, at best, user consternation due to slowness or unavailability. At worst, it could result in fiscal damage—or even jail time due to data loss.