[Ziroc]

Here is some information on NON-Dual Optical Mice:

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The increasing popularity of large 17 and 19-inch monitors has created a problem for mouse users. The large screen settings used with these monitors mean the mouse must be moved farther than normal to point at something across the screen. The problem is, large movements can be physically uncomfortable.

Most optical mice have a resolution of 400 DPI (Dots Per Inch), meaning that without software compensation, the cursor will move 400 pixels across the screen for every inch the mouse is moved on the desktop. For small screen settings this is fine, but for large settings it means the mouse must be moved abnormally far.

To compensate for this, mouse software drivers include speed and acceleration controls (accessed in the mouse properties dialog) to amplify how far the cursor moves in response to how fast the mouse is moved.

For example, these controls could be set so when the mouse is moved slowly across the table for one inch, the cursor will move 400 pixels across the screen. As the mouse is moved faster, cursor movement will be increasingly magnified up to the point where it will travel 800 pixels or more per inch of mouse movement.

The problem with this is, as the settings are increased, pointing accuracy is decreased and the cursor becomes more difficult to control. In the example above, when the mouse is moved quickly for one inch, the cursor effectively skips every other pixel in order to travel a screen distance of 800 pixels. Thus pointing accuracy is reduced.
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