Hi!

>these are a different MMU and a different approach to DMA.
Sun uses the build in MMU of the 68030 chip, while they used
their home-brewn MMU in sun3 (Motorola was said not to be
able to deliver THEIR MMU in the early sun3 days).

I've noticed, that the 3/80 is much worse in doing DMA
than the 3/60!!! Don't ask me why.
The 3/470 does have a I/O-Cache and is doing DMA very well!

>The Sun3x architecture contains two possible SCSI devices:
No. Emulex in the Sun3/80. You can steal THAT from Sparc2.
The 3/470 does have no onboard SCSI, but uses VME-bus
controllers. Steal si, xd and xy from the sun3 port.

>There are also two possible Ethernet controllers.
Yup! The AMD is the same as in the 3/60, the Intel the
same as in the 3/1XX and 3/2XX.

>The 3/80 contains a (yet unknown) parallel port
I don't know exactly, but it should be identical to the
Sparc printer port of the Sparc2.

BTW: The 3/80 is a nice Sun, comparable to the 3/60.
But the 3/470 is a great machine! It is nearly double
as fast as the 3/60 and does have a couple of unique
features: The I/O-Cache, the VAC (256 kByte) and a
unknown bus on the CPU board!!!
Besides this, it does have a P4 bus too.

Peter