[Simh] Standalone boot on vax8600?

[Matt Burke]

On 08/07/2014 12:50, Johnny Billquist wrote:
> On 2014-07-08 01:50, Henry Bent wrote:
>> How are standalone programs loaded and run on the 8600?  On the 7x0 I
>> can do "load -o boot 0" and "run 2" and that will run a standalone
>> boot.  When I do that in the 8600 sim I get a newline and then the
>> program just loops forever.
>>
>> Alternately, does anyone know the right way to load bootblocks on an ra
>> disk in Ultrix 1 or 2 so that I can boot off of the disk directly?
>> Everything I've tried just ends up giving a "%BOOT-F-Unable to locate
>> BOOT fil" message from vmb.exe.
>
> VMB needs to have R5 set to specific values to boot Ultrix.
> If I remember right, bit 3 (0x8) needs to be set in R5 in order for
> VMB to just load the boot block from the device and start executing
> that instead of trying to look for specific files inside a Files-11
> filesystem.
>
> But on a rel 86x0, you can also load other binaries from the console
> device, and just start them. For old versions of Ultrix, I seem to
> remember that this is what they did, before VMB gained the capability
> to boot from a boot block.
>

The value 8 is correct for R5. To boot this in simh use:

sim> b rq0 /r5:8

On a side note I think this flag is not required on later VAX system
such as the MicroVAX II. The ROM code seems to work out what to do.

'load -o' is supported on the VAX 8600 so I suspect there is another
issue. It could be a problem with the console device as I think someone
has previously mentioned that there are some issues with my
implementation (unless this been fixed now?)

Matt