thank you - a perfect answer about a serial mouse as a second mouse on a laptop. you:

http://www.xfree86.org/4.3.0/RELNOTES4.html


A new section called ServerLayout has been added to allow the layout of the screens and the selection of input devices to be specified. The ServerLayout sections may also include options that are normally found in the ServerFlags section. Multiple ServerLayout sections may be present, and selected from the command line. The following example shows a ServerLayout section for a dual-headed configuration with two Matrox cards, and two mice:

Section "ServerLayout"
Identifier "Layout 1"
Screen "MGA 1"
Screen "MGA 2" RightOf "MGA 1"
InputDevice "Keyboard 1" "CoreKeyboard"
InputDevice "Mouse 1" "CorePointer"
InputDevice "Mouse 2" "SendCoreEvents"
Option "BlankTime" "5"
EndSection