Semi automatic trans missions

I don't know the depth of detail that you want to i'll just keep it simple. There are essentially 2 types which split the the gap between traditional automatic and manual. There are semi-auto's used by mercedes, gm, vw, and the like which are just automatics that enable you to select gears on your own. The key difference with these systems is that they still use a torque converter and ATF. Now i am guessing that you are more concerned with E-Gear used in L-cars, which is very similar in concept to the F1 transmissions that Ferrari uses. These systems you can basically think of as a manual transmission (with a clutch or clutches) but the computer controls clutch actuation and gear changes, and the paddles control the computer.