For example, an eSATA port multiplier allows multiple external SATA drives to be connected to one eSATA port on the computer. Also called a "port expander," another example is a USB hub ...

Sure enough, when he plugged the port multiplier board in (after a bit of what he refers to as “professional wiggling”), the appropriate entry showed up in lspci. But there was a problem.

The SiI3723 SteelVine Series 3 Core SATA 1:2 port multiplier supports host and device rates of 1.5 Gbps or 3 Gbps with auto-negotiation, giving system designers and end users SATA hard disk drive ...