Dumping Images of my VAX-11/730's Drives?

Peter Coghlan cctalk at beyondthepale.ie
Fri Mar 11 05:42:49 CST 2016

> > If you get TCP/IP networking like Multinet (ie not like CMUIP) running, you
> > should be able to use FTP, rcp or maybe even TFTP to move a VMS BACKUP save
> > set to another system.  The snag is you need enough scratch space to create
> > the saveset on the 11/730 before you transfer it.
> Well, there's the problem: I don't have scratch space, since all of the hard
> drives are precisely what I want to image.

Another option I forgot is that if you have Multinet installed, it can do RMT
(remote tape over TCP/IP) which VMS BACKUP can use to write to a tape drive on
a remote system.  I don't know if the other TCP/IP stacks for VMS can do RMT
but I'm pretty sure CMUIP can't.  However, if you don't already have a suitable
TCP/IP stack installed, it's going to equally difficult to get it installed as
to do the backup.

> > C-Kermit for VMS might be able to do this - I can't recall.
> Getting it onto the machine in the first place might be a challenge!

I think C-Kermit and/or the earlier Kermit-32 for VMS came with some sort of
minimal hex loader which can be typed in to cope with this issue.

> I can boot either 7.3 from the R80 fixed drive, or 5.2 from an RL02 pack. So
> in theory, I should be able to boot from each of them to image the other.
> There might be TCP/IP support on the 7.3 installation, but I doubt there's
> any TCP/IP support on the 5.2. I hope that the DECNET support is there on
> both installations for the ethernet card.
> I set up a VM on my Mac running Ubuntu with DECNET support installed.
> Despite being orphaned several years ago, it still seems to run. So I think
> that trying to bring up DECNET on the VAX might give me options. I was
> thinking that if nothing else, if I can log into the VAX remotely via DECNET
> and log the terminal output, then maybe I could just DUMP a foreign-mounted
> volume and then write some throw-away program to transmogrify the hex dump
> into a block-level image. It would be slow, but I hope it would at least be
> quite a bit faster than dumping over an async serial port.
> If I can write a file from the VAX to that Ubuntu VM via DECNET, then maybe I
> can just COPY a foreign-mounted volume to a file on the VM. I don't know what 
> capabilities the Linux DECNET support gives me yet, but if I can do this then
> that should be a good option. I wonder if I can image tapes that way, too?

COPY will give up if it encounters a bad block on the disk and it will also be
difficult to ensure the resulting image is a valid copy of the disk.  BACKUP to
a saveset over DECnet will keep going despite errors and will also include
extra overhead to allow the integrity of the saveset to be verified in case it
gets damaged later.  Using BACKUP will also allow restores of particular files
to be done if required rather than having to restore the whole disk even if
only a small number of files are damaged or inadvertently deleted.

> > Clustering is pretty simple when you know how but if you don't want to get into
> > configuring a cluster, a DECnet connected system or emulated system would
> > probably be the way to go.  Configuring DECnet on VMS can be done very easily
> > with surprisingly little understanding of what is going on and is less
> > invasive than configuring a cluster.
> You had me at "surprisingly little understanding of what is going on"! This
> sounds like the thing for me to try next.

Configuring (phase IV) DECnet is as simple as giving the command:


and answering the questions.  Suitable default answers should be provided for
most of the questions and this is why little understanding of what is going on
is required :-)  Don't worry about not understanding the long list of commands
it comes up with to carry out the configuration either.

You can try the above just to see the questions and then answer "NO" at the end
when it asks if you want the commands to be executed.

If DECnet is already installed, it is probably already configured and the best
thing to do would be to configure the Ubuntu end to suit.  Give it a different
DECnet node address in the same DECnet area.

DECnet on VMS needs a license to be loaded, at least on the V7.3 system.  Do a:


and look for DVNETEND, DVNETRTG or DVNETEXT.  VMS hobbyist licenses can be used.

> > On VMS, any file, including a BACKUP saveset can be specified as being located
> > on a remote DECnet node, so it is possible to run BACKUP on your 11/730 and have
> > the output saveset situated on a different VAX / Alpha / Itanium / emulated
> > system running VMS or on a unix or other system capable of running DECnet well,
> > (ultrix?), even a PC/Macintosh running DOS/Windows/Macos and DEC Pathworks.
> That sounds very promising!

A possible issue with BACKUP is that it will want the saveset to have a
particular fixed record length and it might not cope if the remote filesystem
does not support this and the remote DECnet implementation does not have a way
to simulate it.  It would be good to make sure it works by backing up a small
group of files to a saveset on the your Ubuntu system and then verifying that
BACKUP on the VMS system is happy to read the remote saveset and list the files
in it.

> Thanks for all of the suggestions! I still have a lot of learning curve to
> climb in the VMS world.

Send me an email if you need more details on any of the above.

Peter Coghlan.

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