Chris,

>can't _get_ KPT page?
>
>i've seen "PT page not entered", but not that one.  "eek."
>(btw: i think i may have fixed the bug that caused the "PT page not
>entered" panic...  if you're seeing _that_, tell me...  8-)

I haven't seen the "PT page not entered" panic.  The panic I was getting 
(when I got a panic at all) was definately "can't get KPT page" from the 
pmap_enter_ptpage() routine.

>You'll note that the current Alpha pmap was created in less than a day
>by taking the hp300 pmap (look at the comments), doing a few global
>substitutes, running it though unifdef, and changing a few things here
>and there to clean it up, make it compile, and wedge it into the
>kernel.  In fact, in my initial pmap code (which i ran for more than a
>year w/o noticing!) I _didn't_ do the modify/reference bit emulation,
>and so paging would have been... a bad thing.  Thankfully, i had
>enough RAM.

We did notice an uncanny resemblance between the Alpha and HP300 pmap 
code :-)

Thanks for the background and explanations of the state of the NetBSD VM 
world.  For better or worse, it greatly helped us to make our "fish or 
cut bait" decision for using NetBSD/Alpha in this particular project.  
(Due to time constraints, we unfortunately had to cut bait.)

dp