right - but the beauty of doing the heavy lifting in simh is that you
add/drop virtual devices as needed.   Make one disk with the VAXstation
bootstrap and another with the 780 style.  Once you know you have a proper
bootstrap, root partition, and /usr partition that will work properly on
the target / you know that now have the bits you need to boot to 'single
user.'  If you are really aggressive, you can create /etc/fstab.780 and
/etc/fstab.vs before you go to the real HW.   Because the key point is the
simh 'virtual disks' are just blocks and dd is your friend here.  You can
build up the bits on the real disk from the known pieces you create
separate files for simh.     Once you have a physical disk with proper bits
boot, then start up to 'single user' and fix up anything that really needs
to be HW specific.   Although a little work in /etc/rc{,.local} can even be
pre-made to automate that by having the script detect with CPU you booted
and ln /etc/fstab to the proper one.

As I said, you should be able to do almost all of the work on the simh
system before you go to the real HW.

Sure beats how we had to bootstrap systems back in the day.  The truth is
we used pretty much the same process to do this type of task, but had to
find a common disk between the 'parent' system and the 'target.'     simh
can make Frankenstein systems that never existed in which adds a layer of
ease, plus you even without that, since its just bits, you can take a
partition from a virtual disk on any geometry and move them to another disk
with a different geometry -- something much harder to do with real
hardware.    Everything here is just SW, which is a load faster and easier
;-)

Good luck,
Clem

On Tue, Apr 27, 2021 at 11:01 PM Adam Thornton <athornton@gmail.com> wrote:

>
>
> On Apr 27, 2021, at 1:51 PM, Clem Cole <clemc@ccc.com> wrote:
>
> Might I would suggest a slightly different path.
>
> Install Quasijarus on a more traditional vax processor with RH style
> disks [RMxx/RPxx] on the simh.   Then add a virtual RZ SCSI disk to the
> simh system [although you might not even need to do that - as simh just
> sees the disk as a linear file of blocks without any geometry].  The trick
> is to make sure the virtual disk is set up so that you have a working
> system/booting system on the virtual disk when changing the processor type
> to match the VAXstation.  Then just DD the image to a real SCSI drive and
> move it to the VAXstation.
>
>
> I’m guessing I will at least have to copy the right bootloader and update
> the fstab, but I’ll copy the disk after installation and then see what
> happens.
>
> Adam
>