It needs system files in the right spot.

Sys a: c:
would work if it was booting from a floppy with one partition.

In your case it might be sys c: d: but you'd have to think about it

I did make sure the BIOS was C: , A:

I even tried it both ways

Not the boot order.
The file system needs the boot sector, io.sys,msdos.sys and command.com in the correct spots
https://en.m.wikipedia.org/wiki/SYS_(command)

Yes, most probably it got corrupted when inserting it into Win10. But that's not a big problem. If you have any other DOS machine, it will be simple to just reinit the DOM there, then plug it back into the CNC. If you don't have any other DOS machine, then maybe try to get the floppy drive working.

Option 3 would be to prep up an HDD image using any virtual machine running in Win10, then image that HDD onto the DOM in Win10. Remove the DOM right after the imaging is successfully done so you reduce the chances of Win10 meddling with it.

Ok, great info!

I think I'm going to try the imaging.

I had bought some parts to build another DOS machine... I'll try and get that up and running.

This is what my screen looks like if it offers any other insights.

I just put DOM in that had previously worked, let it run for 5 minutes... and now I get this.

I don't know how, but when this DOM was plugged into the IDE reader in Windows 10... even though I didn't save anything too it... just opened drive and copied contents... W10 must have re arranged it? Weird

Hmm.
2 floppies and hdd type 47.

Tried setting the hdd to auto instead of 47?

It doesn't give me that option for auto detection.

Here are my other BIOS screens

There is auto detection hdd in a separate option, which I used to get me that "47"

But it's not continuous auto detected every time you boot.

Just a thought, if you are trying to reinit the DOM, maybe a Windows98 BootableCD in your Windows10 machine would do the job if you have an IDE port. You can boot Win98 but don't actually start the setup program and go into DOS 7 prompt and fdisk /mbr and sys C: from there. That shouldn't mess anything besides the boot sector on the DOM.

maikolator wrote on 2025-03-31, 21:41:

Just a thought, if you are trying to reinit the DOM, maybe a Windows98 BootableCD in your Windows10 machine would do the job if you have an IDE port. You can boot Win98 but don't actually start the setup program and go into DOS 7 prompt and fdisk /mbr and sys C: from there. That shouldn't mess anything besides the boot sector on the DOM.

I have a Windows XP laptop, will that work? I don't have W98

Something to be aware of is that the system wasn't necessarily using the autodetected settings for type 47.
Other geometries would have worked, but you can't just change them and continue to boot since DOS/the MBR are sensitive to the geometry.
It was common knowledge back then that you couldn't move HDDs between machines. It isn't clear whether Windows corrupted something on the disk, or if the type 47 settings were lost or overwritten somehow, especially as you experimented with the SD-IDE.

Thanks for information Jake.

So much to process, not the computer... me! 🤣

A friend is going to try get the DOM working and Bootable for me.

I'll update this thread.

When I get DOM back, should I auto detect hard drive? It will be a completely new DOM.

I know these questions are trivial for you guys. Thanks for helping, I am picking things up!

the CHS information for the partition is contained in the partition table, but trying to get what the original type was from that might be a trick.

For setting a new one up, I would definitely see what the BIOS of the 486 detects it as, write it down in CHS format, then use the windows box to disk image it. (I assume it's an appropriately small DOM...) I would then put the disk image file in a virtual machine, like virtualbox or vmware with that same CHS configuration, get it all set up there, where you can use image files for the various floppy disks you will need (Since you dont have a working drive on the 486), Image the then set-up image BACK onto the DOM, then connect it and cross your fingers.

Got a photo of the dom?
Model number?

JonnyQuest wrote on 2025-03-31, 21:53:

I have a Windows XP laptop, will that work? I don't have W98

I don't think XP can make it bootable.
But, afaik, XP can make a floppy disk bootable.

DOS, Windows 95, 98, Me, NT, 2000, XP and 2003 do write proper CHS partition tables. You can use the DOM safely with them.
Windows Vista, 7, 8, 8.1, 10 and 11 do NOT write proper CHS partition tables. (They write megabyte aligned partitions instead of cylinder aligned ones.) DOMs used (for partitioning and formatting) may make them unusable for systems that expect classic CHS partitions.

To recover a cleaned disk you can clean it with diskpart (on the latter systems) and with fdisk on the older systems.
In the older systems please turn off power after you have removed all partitions of the DOM. Then turn it on again and create the partition(s).
Basically you should create the partitions directly on your target system.

For your old DOM it really looks like the type 47 information in BIOS was lost.
Which values do you have for your type 47 configuration?
Is it something like 1023 cylinders, 16 heads, 63 sectors?

You can kinda use xp.
But you need a very old version of virtualpc 5 or 6 iirc, and to mount the entire raw disc.
Then a 9x iso, boot to the dos part and sys c: should fix it.

This might be beyond ops skills though

I actually took a picture of my working DOM's BIOS settings before I started this mess.

But it's obviously now a lot more too it than that.

When I purchased the new DOMs for backup purposes, I did pay attention to sizes.

I'll take pics of them soon.