The mouse was invented by Douglas Engelbart in 1964. Its working principle is that the roller drives the shaft to rotate and causes the rheostat to change its resistance. The change in resistance generates a displacement signal. After processing by the computer, the cursor indicating the position on the screen can move. Because the device drags a long line like a mouse (like a mouse's tail), Douglas Engelbart and his colleagues nicknamed it "Mouse" in the laboratory. He also thought at the time that the mouse might be used in the future. It was widely used, so it was named "Display System X-Y Position Indicator" when applying for a patent. However, people felt that the name "Mouse" was more friendly, so the name "mouse" came into being.