Re: Can you MOP boot an install kernel directly?

[Anders Magnusson <ragge%tethuvudet.se@localhost>]

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 included in 
> > 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