After nearly a year of research and design discussions, we (Gordon Ross
and Jeremy Cooper) are pleased to announce that the NetBSD port to the
Sun3X architecture has reached a major milestone.  The current
kernel boots up to the point just before mounting the root filesystem.
At this stage it is stable enough to facilitate the development device
drivers.

Here are answers to a couple of questions we anticipate:

Q. What machines are in the sun3x architecture?

A. The machines that belong to the sun3x architecture are the Sun 3/80 and
   3/470.  The 3/80 is a desktop `pizzabox' unit, while the 3/470 is a
   deskside chassis.

Q. Why is there a need to separate the sun3x port from the sun3 port? 

A. The sun3x architecture was developed at the time when Sun had just
   begun investing in the SPARC architecture.  It appears to have been a
   safety net - a platform that Sun could expand should the SPARC have
   failed to catch on.  It contains many SPARC-like device features but
   retains a sun3 CPU - a Motorola 68030.

   The addition of the SPARC-like devices changes the operation of the
   lower levels of the kernel significantly from the sun3.  Most notably
   these are a different MMU and a different approach to DMA.  Given
   the amount of code needed to dynamically incorporate these changes
   into a single, unified kernel, and given the speed of the CPU and
   RAM capacity of the sun3 and sun3x, it just isn't worth sacrificing the
   compatibility for the efficiency.  On machines with faster processors
   (such as the SPARC), this hinderance would not nearly be so noticeable.


Q. What device drivers are needed?

A. Much of the standard sun3 devices, such as the Zilog serial drivers,
   have been ported.  The major devices that need to be implemented or
   debugged are the SCSI and Ethernet controllers.

   The Sun3x architecture contains two possible SCSI devices: an Emulex
   chip used in model 3/80, and an unknown chipset in the 3/470.  The
   Emulex is probably identical to that used in most SPARC 4Cs.

   There are also two possible Ethernet controllers.  The Am7990 in the
   3/80 and an Intel chip in the 3/470.

   The 3/80 contains a (yet unknown) parallel port chipset which is
   probably identical to the one found in the SPARC IPX.  (Do not quote me
   on this.)  Once this driver is written, it should be beneficial to both
   ports.  This is not nearly as crucial as SCSI and Ethernet.

-Jeremy Cooper