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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年08月04日 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年08月04日 16:24, Anders Magnusson wrote:
Den 2025年08月04日 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
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