At one time, almost all storage was directly attached to servers. Whether that was through disk drives in the server enclosure itself, or external racks directly connected, there was a clear 1:1 mapping between server, application and dedicated storage resources.
Over the last twenty years, the pendulum has swung in the opposite direction: intelligent external storage arrays that share resources across multiple applications and servers. I can still remember back in 1995 trying to convince people that shared storage was better than the dedicated kind, and it certainly wasn't easy :)
But now, there are clear signs that the pendulum has started to move back: intelligent shared storage, but without the familiar external storage array.
And I've now been asked more than once -- are servers the new storage?
The idea of using familiar, commodity-based servers to provide shared storage services has repeatedly become popular -- and then faded -- but it's not the same this time -- the motivations are very different.