Does the 27-inch iMac (MC511LL/A) have a true thunderbolt port or just a mini-display port? I'm trying to connect a thunderbolt external drive to my Mac:

http://www.everymac.com/systems/apple/imac/specs/imac-core-i5-2.8-27-inch-aluminum-mid-2010-specs.html

However, the disk is not being recognized. I suspect that the "thunderbolt" port on the back of this iMac is really a mini-display port.

Thank you.
There's an FAQ on the Apple Support page: http://support.apple.com/kb/HT5219?viewlocale=en_US&amp;locale=en_US#4 Since your Mac is Mid 2010, it does not have a thunderbolt port.