Using Cinema Display connected to external drive
Virtually my only complaint about the 11in 2012 MacBook Air is that the solitary Thunderbolt port must double up as a DVI connector for an external display. This means disconnecting the monitor every time I wish to plug in an external Thunderbolt disk.
My 24in Cinema Display is about five years old and, of course, has no Thunderbolt capability. Instead, the DVI plug from the display is connected to the Thunderbolt port. My theory was that it should be possible to piggy-back the display through an external Thunderbolt device (such as a disk drive) that had dual Thunderbolt sockets.
I asked around, including chatting to staff at two Apple stores, but no one could confirm whether or not this would work. So I decided to try for myself. I can confirm that it does indeed work perfectly. About the only snag with the setup is that the DVI connector from the display's integral cable is relatively short, as are the power and USB cables. They are intended to save space when connected to a laptop or desktop Mac.
This means that the external disk drive, in my case a LaCie 240GB SSD, must sit next to or behind the computer. The standard Apple Thunderbolt cable then connects to the computer and is far too long, which is rather untidy. Still, this is a small price to pay for the convenience of doubling up on the Air's solitary Thunderbolt port. The answer would be a Thunderbolt male/female extension cable but as far as I know such a thing doesn't exist yet.
Another solution to the whole problem is to swap the old Cinema Display for a new 27in model which does include a Thunderbolt display for attaching other peripherals. However, the current model is still offering only USB 2.0 capabilities when all modern Macs have USB 3.0. I am therefore sitting on the fence until the CD is updated.
by Mike Evans, 14 January 2013