dnl	$OpenBSD: prep,v 1.9 2008/08/18 23:19:15 miod Exp $
VAX machines don't generally need any specific preparation. You will need
to properly identify the console port on your machine.

Machines without frame buffers (i.e. everything but VAXstations) use serial
port 0 as the console port. However, it is possible to select port 3 instead,
by moving the S3 switch on the back of the machine in the up position. Not
all models have such a switch, though.

Machines with frame buffers (i.e. VAXstations) have a similar S3 switch,
and will either use a serial console connected to port 3 (usually labeled
as the printer port) if the S3 switch is in the up position, or will use
the keyboard and frame buffer console, if the S3 switch is in the down
position. Be warned that early VAXstation 3100 models do not have a hole in
the enclosure to access the switch, and will need to be opened for the
switch to be flipped.

There are two exceptions to the above rule, however:

- VXT2000 machines have a W3 jumper on the motherboard, near the power supply
  connector. When the jumper is open, the VXT2000 will use the keyboard and
  frame buffer console (this is the factory configuration). Shorting the
  jumper will switch to serial console on the DB25 serial connector, and will
  disable the frame buffer.

- VAXstation 35x0 do not have a permanent setting to force console on the
  printer/console serial port. It will, however, default to serial console
  if the graphics option boards are removed from the machine, or if the
  ``Halt'' button on the maintainence panel is kept pressed during powerup
  or reset, until the I/O panel led indicator displays `B' and output
  appears on the serial port.

Note that, if the frame buffer in your VAXstation is not supported, OpenBSD
will use serial port 3 as the console, as if the S3 switch had been in the
up position.