[Simh] Standalone boot on vax8600?

[Johnny Billquist]

On 2014-07-09 02:31, Matt Burke wrote:
> 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?)

I have played some with the simh 86x0 implementation, but I don't think 
I've checked much about the console device. But I don't think that 
should matter. Once you've loaded the binary from the console device, 
the console device isn't used any more on the real machine.
Older versions of NetBSD used to boot that way, and you just loaded the 
boot file from the RL02, and started. And I seem to remember that it was 
started at address 2. But that of course depends on the boot image...

And the boot image in turn knows how to read an FFS file system, and 
continued to load /vmunix from there (or whatever name for the kernel it 
was looking for).

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
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