[Solved] "Non-system Disk Or Disk Error" after overwriting files on an MS-DOS partition \ VOGONS

[Solved] "Non-system Disk Or Disk Error" after overwriting files on an MS-DOS partition

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First post, by VioletGiraffe

Posted on 2019-10-06, 10:49

VioletGiraffe Offline

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Getting this error after restoring my system partition from backup, I don't understand what I broke and how to fix it. My "backup" is simply an archive of all the files on the disk. I reasoned that backing up the boot sector and partition table is not a concern right now since I'm not going to touch them, I just need the files and their contents. But after restoring from this backup, which means unpacking this archive back to the drive replacing all existing files, I get this error ("Non-system Disk Or Disk Error").

The partition is active:
qq2J2Hn.png?1

The boot sector seems to be in order (makes sense, there's no way I could have broken it by simply moving the files around in Windows Explorer):

So what did I break? Some file attributes, perhaps? What is the bootloader checking for to conclude that the disk is not bootable?

Last edited by VioletGiraffe on 2019-10-06, 11:56. Edited 1 time in total.

Reply 1 of 6, by jmarsh

Posted on 2019-10-06, 11:00

jmarsh Offline

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Either IO.SYS or MSDOS.SYS (or one then the other, I forget the details) have to be located first in the root directory entry. Blindly copying files doesn't ensure they will end up in the same order.

Reply 2 of 6, by Grzyb

Posted on 2019-10-06, 11:00

Grzyb Offline

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When do you encounter that error? While trying to boot off that disk?

There are some special requirements about location of IO.SYS and MSDOS.SYS files, so you can't simply extract them out of archive, you need to install them eg. with "SYS C:" command.

Żywotwór planetarny, jego gnijące błoto, jest świtem egzystencji, fazą wstępną, i wyłoni się z krwawych ciastomózgowych miedź miłująca...

Reply 3 of 6, by VioletGiraffe

Posted on 2019-10-06, 11:03

VioletGiraffe Offline

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jmarsh wrote:
Either IO.SYS or MSDOS.SYS (or one then the other, I forget the details) have to be located first in the root directory entry. Blindly copying files doesn't ensure they will end up in the same order.

Oh, shoot. I might have trouble finding a tool to manually patch the file allocation table...
So basically, my method of backing up should work as long as I don't touch these two files?

Huge thanks for the tip!

Reply 4 of 6, by VioletGiraffe

Posted on 2019-10-06, 11:04

VioletGiraffe Offline

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Grzyb wrote:
When do you encounter that error? While trying to boot off that disk?

Yep.

Grzyb wrote:
eg. with "SYS C:" command.

Is that something I can run while booted from an MS-DOS diskette? Or how do I do this?

Reply 5 of 6, by Grzyb

Posted on 2019-10-06, 11:13

Grzyb Offline

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VioletGiraffe wrote:
Is that something I can run while booted from an MS-DOS diskette?

Exactly.
Just boot from the first MS-DOS diskette, it will launch some installer program - so exit from it, and enter "SYS C:"

Żywotwór planetarny, jego gnijące błoto, jest świtem egzystencji, fazą wstępną, i wyłoni się z krwawych ciastomózgowych miedź miłująca...

Reply 6 of 6, by VioletGiraffe

Posted on 2019-10-06, 11:31

VioletGiraffe Offline

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That helped, thanks a lot!

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