The Motherboard of the Xerox 8010 Optical Star Mouse

Here is evidence that the two-button Star mouse, indeed, descends from the Alto prototype. There is a vacant slot for a third button in the middle of the mouse motherboard. Two tiny white switches on the black blocks provide the left and right mouse button clicks. The board measures 1.75 x 3 inches, much smaller than this enlargement.

On the left, the clear plastic block houses the optical sensors. The number 9 41 is stamped on the bottom left corner.

Dave Curbow's site gives an amazing history of the Xerox Star computer with many photos and research papers. Among the fascinating details are the function keys on the 8010's keyboard -- quite unlike our standard today. www.digibarn.com/friends/curbow/star/.