Synaptics shows off 10-finger gestures for Windows 8

Keeping track of that many digits requires a touchpad area of at least 3.9" x 2.2" (100 x 56 mm). Synaptics also claims that its InterTouch interface is an essential ingredient. Old-school PS/2 touchpad interfaces can only register four finger contact points and track two fingers in real time, the company says, but InterTouch uses "existing industry standard, higher-speed bus interfaces"—my money's on USB. InterTouch is apparently an open architecture that other touchpad makers are free to use.