How do I boot off of a 2nd controller?

[Michael I. Bushnell]

In article <10627 at mimsy.UUCP> chris at mimsy.UUCP (Chris Torek) writes:
>In article <3661 at bloom-beacon.MIT.EDU> nessus at athena.mit.edu (Doug Alan) writes:
>>... boot a VAXstation-II from a disk drive on a second disk controller.
>
>Ultrix may support several uda50 controllers on one bus.  4.2 and
>4.3 BSD do not.  In 4.xBSD, one does

4.3 BSD DOES support multiple uda controllers. All our Microvax-II's
have two controllers: RQDXn and something like an Emulex QD-32.

4.2 BSD doesn't support the Microvax, and I don't know what it does
for a big vax.

>>... I get the Unix boot prompt:
>>
>>	Boot
>>	: ra(4,0)vmunix
>
>or more generally,
>
>	xx(y,z)pathname
>
>where `xx' is one of `hp' `ra' `up' and a few others.  `z' is just
>the partition (on disks at least).  `y' is computed as
>
>	8 * bus_adapter_index + slave		(note 1)
>
>Hence ra(4,0) is adapter 0 (uba0) unit 4 (slave 4).  Note that
>there is no room for a controller index!

The slave is on the controller booted.  Here is how you boot from the
second controller:
 
>>> b dub0  -- Read boot block from second controller, first disk

Loading ra(0,0)boot  -- Reading UNIX boot from first disk, first partition
			of the SAME controller the boot block came from

Boot
: ra(0,0)vmunix    -- Load vmunix from first disk, first partition of the
			SAME controller the boot block came from.

We do this all the time.
				Michael I. Bushnell
				mike at turing.unm.edu
				{ucbvax,gatech}!unmvax!turing!mike

				HASA -- "A" division