Review of Linux Compatibility
The Kensington Orbit is a trackball, which is connected via USB. It is supported by Linux and has the USB ID 047d:2048
Bus 001 Device 012: ID 047d:2048 Kensington
The trackball does not need separate drivers, instead it will be activated automatically as soon as plugged in (e.g. Ubuntu 10.04).
Unfortunately, the is only equipped with two buttons. Internally, the Kensington Orbit is read out like a 5-button mouse, where input 4 and 5 are used to transmit the movement of the scroll wheel. The two buttons are used for input 1 and 2.
A middle button is not foreseen but will be missed during the general Linux usage, e.g. for copy & paste. Who hesitates to add a mechanical middle mouse button by himself, has to make a reallocation of the already available buttons. This can be done with the tool xinput, which can emulate the middle mouse button
xinput set-int-prop "Kensington Kensington USB/PS2 Orbit" "Evdev Wheel Emulation Button" 8 3 xinput set-int-prop "Kensington Kensington USB/PS2 Orbit" "Evdev Wheel Emulation" 8 1
However, a reliable Copy & Paste is not always achieved with this approach. In this case a more complicated reconfiguration of the X-Servers has to be carried out.