DR-DOS

[Tomasz Rola]

On Fri, Nov 17, 2017 at 02:30:20PM +0100, Liam Proven via cctalk wrote:
> I hope this is vintage enough.
[...]
> VBox mounts that. But it won't boot, nor in VMware  -- it just
> displays 2 dots and freezes.
> 
> Embarrassingly late in the troubleshooting process, I've found why.
> 
> I didn't think to check what was on the image! Foolish of me.
> 
> I mounted it on a pre-booted VM and looked, and it's blank! There's
> nothing in the image at all.
> 
> So, I mounted the empty image file as a loop device, copied the boot
> files in there and then the rest of the files in the distro archive.
> 
> And lo, it works! It boots my VM just fine, and it's now running 7.01-08.

Please excuse me if my remark is unnecessary, but if I read you right,
you have: 

1. Downloaded "empty" disk image - which apparently boots enough to
display two dots

2. Copied system (DOS) files on it (say, from backup)

3. You have not erased the boot-sector-from-the-i-net? So it is there
and still boots the (now fully functional) DOS?

If so, perhaps you should start over from totally new, empty image?
Not copy from your currently working image, but from your backup. Just
in case. Or at least try to disassemble the boot sector to see what it
is doing (I have no idea how, but somehow it must be possible).

"Things" can escape from VMs. I have plenty of Xen warnings and bug
descriptions in my old mailboxes, chances are there will be more.

> All I need to do now is work out how to make the hard disk bootable,
> and I'm in business.

Boot some other OS, (I am partial to GRML Linux, well packed with
rescue stuff and more - https://grml.org/ ); + fdisk, mark bootable?

> The DR-DOS 7 SYS command won't do it, as the files aren't named
> IBMBIOS.COM and IBMSYS.COM -- they're DRBIO.SYS and DRSYS.SYS.
> 
> I copied them to the expected names. SYS completes but the disk won't boot.

Perhaps you should try again, copying one file each time, in the right
sequence (I do not recall, which one, but only two files, similarly to
how sys would do it). I did such "manual sys" once on MSDOS 6 (5???)
floppy and it worked (booted).

> Next step will be to try with Norton Disk Doctor.

Watcom C?
DJGPP?

I keep promising myself to do such stuff one day, only with FreeDOS,
plus some utils to refresh my long forgotten i386 assembler. So, it is
probably FASM nowadays. And some editor which is at least minimally
usable... Or some really cheap alternative, with the same under
DOSBOX.

-- 
Regards,
Tomasz Rola

--
** A C programmer asked whether computer had Buddha's nature.      **
** As the answer, master did "rm -rif" on the programmer's home    **
** directory. And then the C programmer became enlightened...      **
**                                                                 **
** Tomasz Rola          mailto:tomasz_rola at bigfoot.com             **