Back in mainframe days, "channel controllers", the subsystems that controlled storage devices, were very programmable. At some points in time, it made sense to off-load as much as possible from the CPU onto the channel controller. At other points in time, the reverse was true.

For a couple of decades, we've had dumb storage devices. Now with some of the NVMe stuff, we're moving back towards smart "storage".

Linux in an SSD is the same idea.