What type of controls does the Sony PSP use?

What type of controls does the Sony PSP use?

Bill Kunkel (Editor-in-Chief, "Tips & Tricks" Magazine) gives expert video advice on: What is the best quality of the Sony PSP? and more...

The primary movement on the Sony PSP is generally controlled through the sort of nub-type controls that you find on laptops, where you basically just put your thumb over it and roll it around. That's what they give you on the PSP. In addition, it's got a set of action buttons located in the usual positions. It doesn't have too many. The controls are generally fairly simple because it's a small screen. Obviously, you don't want to overcomplicate the process of handling these tiny little buttons and these tiny little controls, so it's fairly simple. Some people might feel that in a lot of games there aren't enough controls. In fact, your thumb can get kind of sore rolling that control nub around.