i stand corrected, from my understanding of sun.  but here is what i have
that made me think that, from the SUN frame buffer FAQ, authored by a SUN
employee (so maybe biased?? <g>)

Q: How can I write to the frame buffer directly?

A: This question comes up regularly, in various forms. Sun does not support
   direct access to ANY of our frame buffers. The frame buffer device
   drivers and interface are considered proprietary and are not publicly
   documented. The only supported way for a customer to access a frame
   buffer is through on of our foundation libraries: X, XIL, XGL or OpenGL.
   There are simply too many problems in allowing direct access by customers,
   most significantly the fact that the code will break whenever the hardware
   changes. By supporting s number of low-level interfaces, Sun performs any
   porting for you, so your code should continue to work regardless of the
   actual platform.

-brian

-- 
"Yes, evil comes in many forms, whether it be a man-eating cow or
 Joseph Stalin, but you can't let the package hide the pudding!  Evil
 is just plain bad!  You don't cotton to it.  You gotta smack it in the
 nose with the rolled-up newspaper of goodness!  Bad dog!  Bad dog!"
                                --The Tick