An eSATA connection is a connection, usually on the back plate of the motherboard, that allows you to connect external hard drives and other devices to it.It's very similar to SATA, although slower.
However, it doesn't transmit power, so if your external hard drive only has eSATA it will need to be plugged in, while USB versions draw power from the system.
Hope this helps you
I think the two purple ports on the motherboard to give you the option to connect a pci or pci express card to it which will give you more "plug n` play" options
But you will need a power supply running to it too.