How do I connect a second hard drive to a 3B2/310?

[Steve Gaarder]

I have a second Wren hard drive that I want to hook up to my 3b2/310. 
There are a pair of connectors on the back that are clearly meant to be
for a second drive.  Does anyone know the details - how should I set the
drive select, for example.  Also, what do I need to do so that the system
recognizes the existence of the drive?  It's already properly formatted.

Email replies; I'll summarize.

Thanks,

Steve Gaarder
gaarder at theory.tn.cornell.edu