The Seagate Dockstar is a cool little ARM based Plug computer.
See also Seagate Dockstar Disassemble for more info on how to take it apart.
To do any real hacking on the Dockstar, you have to connect the serial console to your computer. I recommend using sparkfun's 3.3v FTDI board to make it easy. Then connect up the matching pins according to the diagram: