PDP-11 disk image question

Bill Gunshannon bill.gunshannon at hotmail.com
Sat Feb 16 12:04:05 CST 2019


On 2/16/19 12:35 PM, Zane Healy via cctalk wrote:
> 
>> On Feb 16, 2019, at 9:10 AM, Lyle Bickley via cctalk <cctalk at classiccmp.org> wrote:
>>
>> Bill,
>>
>> On Sat, 16 Feb 2019 13:55:10 +0000
>> Bill Gunshannon via cctalk <cctalk at classiccmp.org> wrote:
>>
>>> So, I used SIMH to do an install of a complete OS on
>>> an RA81 disk.  I would like to  move this to a real disk
>>> and try it on a real PDP-11.  Is there a way to do this
>>> using dd on a BSD machine?  I tried but it created a
>>> non bootable system.  Well, actually, it starts to boot
>>> but then fails very early in the startup process.  I used
>>> "dd if=filename of=raw-device bs=1024".  Could it be that
>>> the block size needs to be something else?
>>>
>>> I know that VTServer and PDPGUI can move disk images but
>>> it would take a week at 9600 baud and I think very little
>>> likelihood of it ever completing successfully.
>>>
>>> bill
>>
>> In order to do this easily, I have SCSI controllers (and disks) on my
>> two primary PDP-11 systems (11/34 and 11/83).
>>
>> 1. I copy the image file I want on a "native" drive using a PC w/SCSI
>> and Linux to a SCSI disk (or removable media) using "dd".
>>
>> 2. I move that drive/media to the SCSI "chain" on a PDP-11.
>>
>> 3. I use RT-11 to move the image from the SCSI drive/media to the
>> "native" HDD.
>>
>> Its a bit cumbersome, but I used this method for years and it hasn't
>> failed me yet ;)
> 
> Like Lyle I have SCSI controllers on my PDP-11/73, and my PDP-11/44.  I’ve actually installed RT-11 and RSX-11M+ from CD-R.  There is another option, and I’ve used this with RL01’s and RL02’s.  With those, I’ve used a MicroVAX II or MicroVAX 3 and VAX/VMS.  I used to have a  dedicated MicroVAX 3 setup with RA73 drives for this.  I still have the hardware, but it hasn’t been used since 2000.  If you have a way to hook the RA81 up to a VAX, I think that would be an option as well.
> 

OK, as usual, I hac caused confusion and didn't get my point across.

let's try with a detailed explanation of what I did that didn't seem
to work.

First, my hardware.  I  have a PDP-11/93 with a CMD SCSI Module and
a BA350 with 6 2GB hard drives.  The Module is set up to present RA81
disks and the first 3 disks have 4 partitions each which should work
out to 12 RA81 disks. (But that last part is unimportant right now!)

I used SIMH to build RSTS V9.6 on a simulated RA81 disk.  I wrote the
disk as a file to a CDR in CD9660 format.  I moved the BA350 and the
CD to a VS3100 running OpenBSD.  I was able to mount the CD under
OpenBSD and see the file containing the disk image.  I used dd with
the command given in my original message (and repeated above) to try
to write the image to a real SCSI disk.  When I try to boot it I get
the RSTS Message "INIT.SYS not found".  The disk was completely blank
to start so the RSTS info must have been copied but apparently not
copied correctly.

Any more suggestions?

bill



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