There is a slight different between the DSG and SMG trannies but both are true manuals. Two clutches are in fact used on DSG but(like in diffs) the clutch is used so sparingly they wear after very long periods of time (50% to 75% longer than a well used clutch.

DSG were actually first developed by porsche but as of late vw seems to have taken credit (even thought they lease the technology from borg)
In the DSG, the gears 1,3,5 are connected and share one clutch, while gears 2,4,6 use the other clutch. Because the connection to the driveshaft (or halfshaft) is more direct and closer in syncronization, the need to manually operate the clutch is eliminated.

SMG's are sometimes assisted electrohydraulically and have been around much longer such as in bmws, toyota and ferrari's f1 tranny(mr2 smg was the model designation for toyota) which means hydraulics shifts the gears faster than your foot, eliminating the need for your foot and clutch pedal and an electronic brain operates this instead of, well your brain.

hopefully I explained that right...but either way they are complete different than the auto due in part because a conventenal clutch is still used but sparingly as opposed to the automatics torque converter

 

good info, thanks.... so things like triptronic are BS, but SMG and DSG (seems line only on german cars) is the real deal. Cool.