[Simh] porting RL01 images to RL02

[Johnny Billquist]

On 2017-02-05 21:07, Clem Cole wrote:
> Going back to the original question (BTW ... everything Paul and Johnny
> pointed out are excellent); but I think you need to step back and think
> a little conceptually about what you are trying to do.

Fair enough. :-)
A bit more detail on what he have, and what he wants to accomplish could 
be useful.

> Ignore simh for a minute and think this through as a thought experiment
> if you had two PDP-11 -- the systems:
>
>  1. which you boot - RK05 based
>  2. one which you can not boot the current OS with the media you require
>     (RL02 - in this case)
>
> How do you move the OS from one system to the other and be able to boot
> both systems when done.   Basically, you a few things (which might be
> satisfied by a single device but conceptually can be with different
> devices that satisfy each action):
>
> 1.) A common media  that both systems understand or some way to transfer
> binary between both systems.
> 2.) Some way to boot the second system with >>some<< OS that can read
> the common media/run the transfer program.
> 3.) Some way to build bootable media for the OS you want to run on the
> media you want.
>
>
> It seems to me the issue here is you have an RK05 in common and RL02 on
> the new system which you can not create. what you need/want.
>
> As Johnny pointed out, trying try to the RK05 bits on the RL02 is
> unlikely to lead to a bootable system, because things like the bootblock
> code is wrong.   Other issues are things like interleaving, file system
> block clustering etc., which can vary depending the target OS and target HW.
>
> So unless you specific tools the create conformant disk images (RL02)
> for the second OS (what ever you are desire - RSX, RSTS, RT11, DOS11,
> UNIX etcc), you are likely to have issues.    When we develop/port an
> OS, this solution is often what we do/is done.
>
> We write tools that run on original host that make images that are
> expected by the target.  This seems to be what you are asking for.   The
> problem is such tools will vary per OS and can vary per target media.
> So, unless /you know exactly what you are doing for both the target OS
> and target media/, you are unlikely to have a lot direct success.
>
> But.....  what I hear you saying is that you need do boot the second
> system with the RK05, and tools to create a bootable file system/regen
> the system for the RL02.     Don't despair -- there are a number of ways
> to do this.
>
> Then build that disk, boot it and then use the RK05 as a common disk
> between the systems.   Johnny will have to answer if you can boot RSX11
> on an RK05, Paul can tell you the same for RSTS, many of us on this
> list, such me can talk you through UNIX if its not already clear as this
> is done all the time there.

Here is where we have the questions. What does he actually want to do, 
and with what?

Moving a system from one type of disk to another, is general, a well 
known and solved problem. There are some limitations to what devices can 
be used as the system boot device, which differs based on OS. But apart 
from that, there is nothing very strange or tricky about it.

But it is not normally done by just copying the raw blocks from one 
device to the other. You commonly boot the OS, and use tools within the 
system to write your new disk, populate it with content, and make it 
bootable.

> But I think the simplest and most fool proof process is this:
>
> 1.) build a bootable RK05 RSX11-M image on system 1.
> 2.) Dismount and remount it on system 2, and boot system 2.
> 3.) Use the RSX11-M disk build tool create a bootable RL02 system.
> 4.) Reboot system 2 using the RL02
> 5.) Then sneaker-net using the RK05 data from the two systems.

Totally agree on steps 1 to 4. Not sure what step 5 is here. But any 
way, I would like to understand what system 1 and 2 is for the OP. I 
almost got the impression that he maybe had some actual hardware, but 
then is passing through simh for some reason, and fiddling with 
different types of disks. Not entirely sure why.

> Since one of the systems is "virtual" using simh, trick is writing the
> common (RK05) and there are multiple ways to do that.

Well, writing the RK05 is sure one "problem" to solve. But I'm actually 
not following what the problem the OP is trying to deal with, talking 
about "porting" from an RL01 to RL02, or even from an RK05 to something 
else.
If simh is involved, he might as well just actually set up the correct 
devices from the start, and not try all this trickery.

> BTW:  Another solution (being a UNIX guy) since the first system is
> simh, would be to add a virtual RL02 to it. And do the regeneration and
> set up all on a virtual RL02.
>
> Then using small UNIX image, and the the common (smaller) disk; bring
> the RL02 image over as multiple parts and put it back together with the
> dd program.    But you'll need a different tool kit and lot more
> knowledge of what's going on under the covers to make that happen.

Not sure what is the first system, or anything, but as simh seems to be 
involved, I'm not sure why you would not do it this way. Set up the 
correct, required devices in simh, and just do it the easy and correct way.

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol