> However, the SBus architecture is
> similar and the Ultra 1 models 140 and 170 (not to be mistaken for 140E,
> 170E and 200E) use most of the same devices as sun4m machines.

Right; a definite first step in a port would be to get the sun4u
kernel stuff working on a Ultra 1 type machine with the machio/slavio
IO instead of HappyMeal, which hasn't got a driver yet that I know of.

> A 32-bit sun4u port is probably only a little more work than the sun3x
> port.  A 64-bit port, such as what the Linux guys are claiming, has
> compiler and toolchain issues and is therefore much more difficult.

I think, but am not sure, that the 64-bit UltraSPARC gcc version
that Sun had Cygnus do has now been rolled into the public
GCC code and is available to anyone.

-george william herbert
Axil Computers
gherbert@axil.com