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How to clone DOS drive?

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jmelson:
I have an old system that runs DOS 6 that runs an X-ray fluorescence machine in a lab.  I am trying to replace the ancient computer with a modern one.
I have cloned the IDE hard drive onto a modern SATA drive, but I get "missing operating system".  I used dd on a Linux system to copy the whole drive contents, including the MBR, partition table and the main partition.  I can't figure out why I get the missing OS error.

I have seen desciption online that I should run fdisk /mbr from a Win95 CD, but I don't have a good one of those anymore.

Thanks in advance for any ideas.
Jon

Twoflower:
Probably the modern computer can't handle the old OS. Especially if the computer has only UEFI with no legacy (old BIOS) support. I think that's the case for Intel Gen 10 Core-I CPUs. And I thing they even dropped some other legacy support since some longer time (e.g. the good old A20 Gate emulation).

One workaround would be to use a VM if the software can work in it.

themadhippy:

--- Quote --- I used dd on a Linux system to copy the whole drive contents, including the MBR, partition table and the main partition.  I can't figure out why I get the missing OS error.
--- End quote ---
Did it copy the hidden files ,seem to recall you had to include the sys command if you wanted to make a bootable disc in the days of dos

jmelson:

--- Quote from: Twoflower on March 25, 2022, 09:48:35 pm ---Probably the modern computer can't handle the old OS. Especially if the computer has only UEFI with no legacy (old BIOS) support. I think that's the case for Intel Gen 10 Core-I CPUs. And I thing they even dropped some other legacy support since some longer time (e.g. the good old A20 Gate emulation).

--- End quote ---
This is a Celeron CPU, and the manufacturer specifically states it has been tested on DOS, Win95 and Win98.
The message "missing operating system" comes FROM the boot code in the MBR, as one can find it when dumping the first block of the disk.
At least on an older motherboard, I get the SAME message from the SATA disk clone, but the original PATA drive boots up and runs DOS and the application perfectly.  So, the REAL problem here is the way I am cloning the disk.  Something about using dd to suck up the whole disk (not SDA1 but just sda, so it gets EVERYTHING on the original drive including the MBR and partition table) is leaving something not quite right in the clone.  I'm guessing there is some pointer to cyl/head/sector that ends up not pointing to the right disk block.
The fact I get "missing operating system" proves the MBR code is executing, but it is failing to find the OS file for the next phase of the boot.
Jon

Whales:
dd'ing the whole disk is a good strategy, assuming you did the entire disk (dd if=/dev/sdx of=/dev/sdy) and not just a partition (dd if=/dev/sdx1 of=/dev/sdy1).  I recommend making a backup to a file (on a modern computer) too.

At a guess:

 * new disk is too big
 * new system has too much ram
 * new system is otherwise too foreign (shouldn't be an issue with IDE boot via BIOS?  edit: but the new disk is SATA, so perhaps check if the BIOS is configured to use IDE emulation or AHCI/RAID/something else for the SATA disks)

I imaged one of my win3.1 boxes a while back and ran into problem #2 whilst trying to virtualise.  Half of the files on the filesystem simply didn't exist, the system would only boot to dos and then complain.  Reducing the RAM magicly fixed this.

For a long time there were HDDs with jumper options to intentionally reduce their reported size.  I believe this was done to workaround software that couldn't handle the high disk size numbers.

It's difficult to get small SSDs/HDDs these days, but you can cheat and use a CF-to-IDE adaptor (CF cards natively implement IDE) or a SD-to-IDE/SATA adapter (probably cheaper and better in the long term, but I have not tried them on old systems/software yet).

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