Question conerning evdev keycode definition & mapping

[Henry Zhao]

I just installed ubunto 8.10 on Tishiba R600.  Running "xmodmap -pk"
I found some keycodes that are mapped to XF* keysyms are also used
in some keyboards in some circumstances.    For example, 
150 is mapped to XF86Sleep. But:

* It is used in xkb/keycodes/fujitsu
* It is used in xkb/keycodes/digital/lk
* It is used in xkb/keycodes/xfree86 (<I16> =   150; alias <COPY> = <I16>;)

Will that cause a conflict  ?  Besides,  I believe keycode 150 is geneated
by a scan code from kernel driver in response to ACPI (Fn + F3) stroke, 
does
that mean the same scan code can be generated in multiple ways  in above
example ?

Also, in "xmodmap -pk",  each keycode is mapped to 6 keysyms, but in
xkb/symbols/*,  they are not mapped to that many (XF86Sleep is mapped up
to 2 keysyms in xkb/symbols/inet).  Why is the difference and what causes
keycode to map to 6 keysyms ?