Re: Can you MOP boot an install kernel directly?

More top-posting :-)

I just tested with simh:
VAX simulator V3.9-0
sim> SET CPU 512m
sim> SET CPU IDLE=NETBSD
sim> load -r /usr/pkg/share/simh/ka655x.bin
sim> SET XQ MAC=08-00-2B-88-77-66
sim> attach xq wm0
sim> boot cpu
libpcap version 1.3.0
Eth: opened OS device wm0


KA655X-B V5.3, VMB 2.7
Performing normal system tests.
40..39..38..37..36..35..34..33..32..31..30..29..28..27..26..25..
24..23..22..21..20..19..18..17..16..15..14..13..12..11..10..09..
08..07..06..05..04..03..
Tests completed.
 >>>b xqa0
(BOOT/R5:0 XQA0



   2..
-XQA0
   1..0..


 >> NetBSD/vax boot [1.12 (Wed Mar 21 18:16:23 UTC 2018)] <<
 >> Press any key to abort autoboot 2
Press '?' for help
 >

so it seems to work :-)

-- R


Den 2025-08-04 kl. 16:45, skrev Johnny Billquist:
> I'll just top-post to be lazy.
>
> First of all, as you know, MOP is the "native" way to netboot DEC 
> machines from back in the day. And MOP sortof fills the place of both 
> DHCP and TFTP in one. But it's more targeted for the explicit need of 
> netbooting and remote management. But in a sense, for VAXen, it would 
> be great if we had the possibility of getting all the netbooting 
> though MOP and not need DHCP and TFTP. Not sure if that is possible, 
> though.
>
> I guess MOP didn't really become that relevant with VAXen until the 
> uVAX II (that one was able to netboot, right?). There were 
> net-bootable PDP-11 systems as well, which also used MOP, and which 
> were earlier. But pretty much all the handling of MOP on those 
> machines were actually located in the ethernet controller itself. The 
> CPU was pretty much just in a tight loop until the controller brought 
> it out of there. But that was primarily for the PDP-11. On VAXen, MOP 
> was implemented in the boot monitors. Not sure you can even use the 
> MOP in the controller itself if you're on a VAX.
> But so, for simh, the controllers do implement at least parts of the 
> MOP on that side. For VAXen, with something like the 3900, the boot 
> roms from the actual machine are included, if I remember right, and so 
> MOP booting will definitely work there no matter what else simh might do.
>
>   Johnny
>
> On 2025-08-04 16:24, Anders Magnusson wrote:
>> Den 2025-08-04 kl. 16:15, skrev Perry Metzger:
>>> On 8/4/25 09:59, Anders Magnusson wrote:
>>>>> Okay, so, I have a VAXstation 4000 VLC I'm setting up and I'd like 
>>>>> to try to avoid needing a full NFS server, rarpd, and all the rest 
>>>>> of that to boot it for installation (and as I am thinking of 
>>>>> cleaning up some of the install tools I might be installing it 
>>>>> repeatedly). One thing that struck me as a possibility was booting 
>>>>> an INSTALL  kernel with an embedded ramdisk directly from MOP, 
>>>>> another option struck me as fixing the network boot blocks so that 
>>>>> they can use dhcp and tftp to download the kernel instead of 
>>>>> requiring a full NFS setup. (Many ports allow this one way or 
>>>>> another, either from the blocks themselves or from mechanisms like 
>>>>> PXE.)
>>>> Yes, sounds like something that would be smooth to have.
>>>> - Adding support for tftp to boot is mostly trivial.
>>>
>>> Also dhcp. Which is also easy enough since libsa handles both. Then 
>>> one can load an INSTALL kernel very easily over the network and 
>>> install that way.
>> DHCP is supported.  Needed to get the address of the nfs server :-)
>>
>>>> - Making the install kernel detect whether loaded via mop or is 
>>>> probably not especially difficult either.
>>>>
>>>> Note that netbooting is something quite new in the vax world :-) It 
>>>> was not until moj@stacken wrote mopd that it could be done at all, 
>>>> before that I used boot on a local media (floppy) that loaded the 
>>>> kernel from a SunOS4 machine. Hence bootparams is also includedin 
>>>> the boot program :-)
>>>
>>> Yah, it's certainly not something people would have wanted to do 45 
>>> years ago but now it's pretty useful.
>> :-)  I think MOP showed up some 5-10 years into the vax lifespan. No 
>> need for it unless you are diskless, which came with MV2000 and 
>> friends (some DEC gurus can probably give better explanations :-) )
>>
>>
>>> Does SIMH support MOP btw?
>> Good question.  A quick grep for MOP in pdp11_xq.c gives a lot of 
>> hits though.
>>
>> -- R
>