uiomove vs. copy{in,out,instr,str}

[Joe Talbott]

I am doing some research on device driver implementation in
DragonFlyBSD.  I am unclear on when to use uiomove and when to use
copy{in,out,str,instr}.  I noticed the character device example; 
/usr/share/examples/kld/cdev/module/cdev.c uses copy... yet hasn't
been updated to use the new cdevsw interface.  I have mostly gotten
the example to work using uiomove but have failed to get the example
working with copy...  From uio(9) is would seem is the way to go.

Joe