<P> Nearly all mice now have an integrated input primarily intended for scrolling on top, usually a single - axis digital wheel or rocker switch which can also be depressed to act as a third button . Though less common, many mice instead have two - axis inputs such as a tiltable wheel, trackball, or touchpad . </P> <P> Mickeys per second is a unit of measurement for the speed and movement direction of a computer mouse, where direction is often expressed as "horizontal" versus "vertical" mickey count . However, speed can also refer to the ratio between how many pixels the cursor moves on the screen and how far the mouse moves on the mouse pad, which may be expressed as pixels per mickey, pixels per inch, or pixels per centimeter . </P> <P> The computer industry often measures mouse sensitivity in terms of counts per inch (CPI), commonly expressed as dots per inch (DPI)--the number of steps the mouse will report when it moves one inch . In early mice, this specification was called pulses per inch (ppi). The Mickey originally referred to one of these counts, or one resolvable step of motion . If the default mouse - tracking condition involves moving the cursor by one screen - pixel or dot on - screen per reported step, then the CPI does equate to DPI: dots of cursor motion per inch of mouse motion . The CPI or DPI as reported by manufacturers depends on how they make the mouse; the higher the CPI, the faster the cursor moves with mouse movement . However, software can adjust the mouse sensitivity, making the cursor move faster or slower than its CPI . Current software can change the speed of the cursor dynamically, taking into account the mouse's absolute speed and the movement from the last stop - point . In most software, an example being the Windows platforms, this setting is named "speed," referring to "cursor precision". However, some operating systems name this setting "acceleration", the typical Apple OS designation . This term is incorrect . Mouse acceleration in most mouse software refers to the change in speed of the cursor over time while the mouse movement is constant . </P> <P> For simple software, when the mouse starts to move, the software will count the number of "counts" or "mickeys" received from the mouse and will move the cursor across the screen by that number of pixels (or multiplied by a rate factor, typically less than 1). The cursor will move slowly on the screen, with good precision . When the movement of the mouse passes the value set for some threshold, the software will start to move the cursor faster, with a greater rate factor . Usually, the user can set the value of the second rate factor by changing the "acceleration" setting . </P>

When was the first wireless computer mouse invented