VAX-11/730 %BOOT-F-Unexpected Machine Check

Mark J. Blair nf6x at
Tue Jun 9 10:15:18 CDT 2015

> On Jun 8, 2015, at 08:58, Peter Coghlan <cctalk at> wrote:
> Standalone backup is a very small VMS environment.  You get a "$" prompt and
> the only command which it accepts is "BACKUP".  You don't get to mount anything
> as BACKUP will perform any mounting needed itself.  I'm not sure but it is
> also possible that only BACKUP /IMAGE works.


My goal here is to figure out what's on the R80 and that RL02 pack, boot them if possible, and extract all of the delicious bytes for archival and examination on my modern machine(s) (primarily Mac). I'm trying to boot the standalone backup tape images because those are what I found that have the same version number as the label on top of the RL02 pack, and are in a format that I can do something with at the moment.

Now, the seller of the system stated that he last run OpenVMS 7.3 (if I recall correctly) on it, so it's possible that's what is on the R80.

The issue that I'm having at the moment is that when I try to boot from either that RL02 pack or the R80, VMB.EXE reports "%BOOT-F-Unable to locate BOOT file". I don't know yet whether there's something not-right about the contents of the hard drives, or I need to configure something (?) so VMB.EXE knows what to look for. The boot scripts on the console boot tape appear to set up VMB.EXE by shoving numbers into some registers prior to loading it, and I have not yet located any documentation about what the numbers mean. I can just see that they're different in each of the scripts. I've only tried the non-conversational boot scripts so far, since I learned about what the xxnGEN scripts were for after my last experimentation session.

I wonder if I might be able to back up the hard drives to an absurd number of emulated TU58 images, so that I could then examine those on my modern machine?

I could probably back up onto magtape, but I don't have another means to read the tapes yet. I have another tape drive (which needs repair) that I'll eventually include in my PDP-11/44 restoration, but that's a big project, far in the future.

I wonder if the VMS5.3 standalone backup might know how to back up to some network device? I have an ethernet card in the VAX, so that might be a way to get data off the machine for examination.

Any suggestions or clues would be greatly appreciated! I'm still learning how to tell the chickens from the eggs.

Mark J. Blair, NF6X <nf6x at>

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