Cannot boot to DOS in a Windows 7 / MS-DOS 7.10 dual boot

#1
I followed the instructions for already having Windows 7 installed and wanting to install DOS to dual boot. I ran into an issue I've seen in another thread where when choosing to boot to DOS, it just goes to a Grub prompt. I then tried the older EasyBCD 2.0 and that didn't work either.

I then saw that it was said that the DOS partition needed to be at the front of the hard drive (which isn't in the documentation for installing DOS and dual booting when Windows 7 is already installed), so I used Gparted and moved the DOS partition to the front of the drive. Still goes to Grub prompt. I tried giving the DOS partition a drive letter, and tried it without as well.

It seems like the auto-entry for the DOS boot menu that points to "NST\AutoNeoGrub0.mbr" just does not connect to the DOS installation.

The DOS partition is 500Mb, FAT32, for MS-DOS 7.10.

Any advice?
 
#3
No, the Windows partition is active. I noticed that it was stated that SATA hard drives will not work for DOS, and this is a SATA hard drive, but the Dual Boot Win7/DOS instructions say they were tested on a computer with a SATA hard drive?
 
#4
I did a Google search on DOS and SATA hard drive and from those comments I will reiterate my earlier comment, the DOS drive must be primary, active and FAT32. From what I read that should satisfy the installation of DOS. Not sure what is the earliest version that would work but most of the comments used a Windows ME boot floppy which, I think, is a DOS 7 boot floppy.
 
#5
I did a Google search on DOS and SATA hard drive and from those comments I will reiterate my earlier comment, the DOS drive must be primary, active and FAT32. From what I read that should satisfy the installation of DOS. Not sure what is the earliest version that would work but most of the comments used a Windows ME boot floppy which, I think, is a DOS 7 boot floppy.
I will try that, but this sounds contradictory to the instructions:

http://thpc.info/dual/win7/dualboot_win7+ms-dos710_on_win7.html

"Also, the Active marker is unaffected by installing MS-DOS 7.10 - your experience may be different, so be prepared to use Fdisk (Option 2), Win7's DiskPart, or your own method of making the NTFS partition Active again. "

Addendum:

All making the DOS partition active did was ignored the boot menu and strictly tried to boot to DOS, to which it gave a I/O error and asked for system disk to be entered. I'll be resetting the Windows partition to active, but not sure what to do from here to make the dual boot work.
 
Last edited:

mqudsi

Mostly Harmless
Staff member
#6
DOS doesn't care if it's SATA - what really matters is how your motherboard presents the drive to the OS.
You should set your BIOS to ATA mode (vs AHCI).
 
#7
DOS doesn't care if it's SATA - what really matters is how your motherboard presents the drive to the OS.
You should set your BIOS to ATA mode (vs AHCI).
This motherboard doesn't have an AHCI mode.

I had yesterday removed MS-DOS 7.10 and reformatted it's partition to FAT16, and then put MS-DOS 6.22 on it. It booted to DOS fine then immediately. I went through the Windows 7 fixes to boot back into W7, and then tried to set the EasyBCD to boot to DOS and it gave "System Disk Error". I think it's missing the Bootsect.dos now. I reverted to EasyBCD 2.0 from someone else's post that said it worked for them, but not for me.

I'm still not sure what I'm missing here. I'd like to go back to having it MS-DOS 7.10 on a FAT32 partition. It is the first partition on the first disk (after the gparted move stated in OP), but I'll be back to the AutoNeoGrub.mbr booting to a Grub prompt.

I even tried setting up the Grub bootloader menu.lst to chainload to boot to DOS (admittedly not sure if I had commands right as I have no experience with that), but it always failed no matter what I tried.

If I have DOS on the first partition, the System Reserve on the second Partition, and Windows 7 on the third partition, how does adding a "Win9x/ME/NT" auto-entry to the boot menu in EasyBCD 2.1 without doing any other configuration make it know where to boot DOS?
 

Terry60

Knows where his towel is.
Staff member
#8
#9
I did not until you linked it. However, I looked at it, and that's not of help to me. I was already choosing the "95/98/NT" instead of "DOS" for the entry type, and I don't have a boot.ini on the dos partition to change. It appears that when I fix the Windows 7 boot properties, it overwrites with it's own bootloader on that DOS partition (BCD files).

I have this:

1st partition - E: DOS, 500mb primary
2nd partition - System Reserve, 100mb
3rd partition - C: Windows 7, primary, active

If I make the DOS partition active, it boots right into DOS fine. If I make the Windows partition active, I get the boot menu with the entries I put in, but not one single entry has been correct for it to boot to DOS. It's always "Invalid system disk", "System Disk Error", etc. I don't know how the autogrub.mbr was supposed to work, but it didn't when I added on the DOS partition to the end of the drive after Windows 7 was installed in the beginning (following the instructions), and it didn't after I moved the DOS partition to the front of the disk either.
 

Terry60

Knows where his towel is.
Staff member
#10
If W7 installed with a 100Mb "System Reserved", that's where it put its boot files.
That's the one that was "active" before you moved things and set up DOS.
Iirc, you need the DOS boot files in the same active partition as W7.
i.e. DOS should be active and you should copy the W7 boot files in with it
Changing the Boot Partition - EasyBCD - NeoSmart Technologies Wiki.
Try it. It copies the files, so you won't affect W7.
 
#11
If W7 installed with a 100Mb "System Reserved", that's where it put its boot files.
That's the one that was "active" before you moved things and set up DOS.
Iirc, you need the DOS boot files in the same active partition as W7.
i.e. DOS should be active and you should copy the W7 boot files in with it
Changing the Boot Partition - EasyBCD - NeoSmart Technologies Wiki.
Try it. It copies the files, so you won't affect W7.
You're right, the System Reserve was active before.

I followed the link you gave and changed the boot partition to the DOS partition, and it errored on both DOS entries I had in the menu. I installed EasyBCD 2.1 build 152 and corrected the entries to reflect Windows 7 on the C: drive and DOS on the E: drive, and now it dual boots properly. Thank you for your help!

My ending question then would be that I originally had just Windows 7 installed, and followed the instructions to add DOS on to the end of the drive to dual boot and it did not...was it because I didn't change the DOS partition to be the boot partition like in this instance?
 

Terry60

Knows where his towel is.
Staff member
#12
I've not tried anything earlier than XP in a dual-boot, so I don't know from experience, but my understanding is that all pre-NT OSs were dependent on being at the front of the HDD and primary. Only since NT was the bootloader able to handle the OS being anywhere else.
I've seen URLs describing being able to boot DOS from somewhere else, but I don't know how, or if it's correct.
 
#13
Dual-boot tip

Thanks also for the tip / suggestions. Nicely done.

- - - -

You're right, the System Reserve was active before.

I followed the link you gave and changed the boot partition to the DOS partition, and it errored on both DOS entries I had in the menu. I installed EasyBCD 2.1 build 152 and corrected the entries to reflect Windows 7 on the C: drive and DOS on the E: drive, and now it dual boots properly. Thank you for your help!

My ending question then would be that I originally had just Windows 7 installed, and followed the instructions to add DOS on to the end of the drive to dual boot and it did not...was it because I didn't change the DOS partition to be the boot partition like in this instance?