Rotation
The N900 has bundled rotation functionalities, so this article applies only to its predecessors. See N900 accelerometer for more information.
Rotation allows you to change the screen orientation between landscape and portrait to all 4 cardinal directions. You may wish to do this to better view a long page of text, allow for easier left-handed operation, for easier reading of certain websites, or a variety of other purposes.
Unfortunately, rotation support isn't bundled with Maemo even though the tablets support hardware screen rotation. Fortunately, installing the necessary packages for rotation support is a relatively easy process.
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