Re: Can you MOP boot an install kernel directly?

I have used a DEC Infoserver to MOP boot and install VMS on many VAXen.
Could NetBSD be setup to do the same?

On Mon, Aug 4, 2025 at 10:45 AM Johnny Billquist <[email protected]> wrote:

> 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
>
> --
> Johnny Billquist                  || "I'm on a bus
>                                    ||  on a psychedelic trip
> email: [email protected]             ||  Reading murder books
> pdp is alive!                     ||  tryin' to stay hip" - B. Idol
>
>

-- 
Michael Thompson