China DOS Union

What the LZ said about implementing dual-boot between the two seems to be installing DOS in the same C drive where XP is installed, but I have divided the hard drive into two primary partitions, C drive (NTFS format, with XP installed) and G drive (FAT32 format, with MS-DOS 7.10 installed), the active partition is C drive. I used the PROBE tool in the XP installation disc to read the content of the first sector of G drive (said to be the boot sector of DOS system), saved it as BOOTSECT.DOS file to C:\, and also added "C:\BOOTSECT.DOS="MS-DOS7.10"" at the end of BOOT.INI. There is a dual-boot menu for selection when booting, but only default XP can boot, when selecting MS-DOS7.10, can't boot DOS, there is just a cursor at the top, nothing else, waited for a long time with no response, please ask everyone where the problem is? Urgent...

The owner of the post is just yourself? For the correct method of installing DOS under XP, please refer to some related posts in the forum.

Hehe, sorry. This post was originally asked as a reply to someone in another section, but then I thought it wasn't appropriate and moved it to this section, so the content hasn't been changed and I called myself "the original poster"~~~
I've read all the relevant posts, but I can't find my problem. That is, XP and DOS are installed in two different primary partitions, and it's done by creating BOOTSECT.DOS by myself. I just don't know where the problem is. I hope experts can help analyze the possible problem areas. Thanks a million~~~

According to what you said on the first floor, it seems there's not much problem. This should be able to boot DOS.

Please confirm a few questions:
1. The extracted boot sector is 512 bytes;
2. How did you format drive g:? Was it formatted under DOS or under XP.

Also, since there are only two partitions on the hard drive, why are they C and G, and what are DEF?

Originally posted by fujianabc at 2006-5-13 11:32:
According to what you said in the first floor, it doesn't seem to be a big problem. In this way, DOS should be able to start.

Please confirm a few questions:
1. The extracted boot sector is 512 bytes;
2. How did you format drive G, under DOS...

The landlord probably means that there are two primary partitions C and G on the hard drive. C is active, and G is inactive. Among them, D, E, and F are all extended partitions. Similar to mine. Hehe...

I don't know if rewriting the master boot record of partition G with Diskgen is this part of the 512-byte boot sector. What tool is more convenient to extract? It seems that Diskgen doesn't have this function.

[ Last edited by martin325 on 2006-5-14 at 10:37 ]

Originally posted by martin325 at 2006-5-14 10:34 AM:

The owner's meaning is probably that there are two primary partitions C and G on the hard drive. C is active, and G is inactive. Among them, D, E, and F are all extended partitions. Similar to mine. Hehe...

I don't know. Rewrite the G partition with Diskgen...

Copying the first 512 bytes of the hard drive to a file with Winhex is the MBR. Also, under DOS, using debug, you can also read the MBR and save it as a file.

It has nothing to do with which partition it is installed on. It should be that your BOOTSECT.DOS file is problematic.

Originally posted by martin325 at 2006-5-14 10:34:

The owner probably means there are two primary partitions on the hard disk, C and G. C is active, and G is inactive. Among them, D, E, and F are all extended partitions. It's similar to mine. Hehe...

My partition is like this. I first used PARTITIONMAGIC to read the first physical sector 102414438 of drive G, then used the PROBE tool in TOOLS of the XP disc to extract the content (512 bytes) of this sector. The last flag is 55AA, which should indicate that this sector of drive G can boot DOS. But I saved the content of this sector as BOOTSECT.DOS to C:\ and added C:\BOOTSECT.DOS="MS-DOS7.10" to BOOT.INI (saved), then when booting, there are two options in the boot menu. But when selecting MS-DOS7.10, it goes black screen, only the cursor is moving in the original position, and it doesn't respond after waiting for a long time. That's the specific situation. Please help analyze again.
(My hard disk was all FAT32 before installing XP and DOS. Among them, C drive is the active primary partition, DEFG are logical partitions. Then I installed XP on C drive and converted C drive to NTFS using the CONVERT command. Then I wanted to install DOS, so I used PARTITIONMAGIC to set drive G as a primary partition (file format is still FAT32). Then I installed DOS on drive G, and then did what was said above, and the result is like that.)

Originally posted by gdufsh at 2006-5-14 02:08 PM:

My partition is like this. I first used PARTITIONMAGIC to read the first physical sector 102414438 of drive G, then used the PROBE tool in TOOLS of the XP disk to extract the content (512 bytes) of this sector, and finally...

Is this boot sector a DOS boot sector? Open it with Notepad and see if there are characters like io.sys, msdos.sys in it. If not, it is not a DOS boot sector.

I encountered the same phenomenon as the original poster today, but the situation is not exactly the same. I want to install XP and MS-DOS 7.10 in the same partition:

On a machine where XP has already been installed, so all partitions are in FAT32 file system. First, save the content of the partition boot sector of drive C, then boot with the Win98 startup floppy disk, SYS C:, then save the boot sector content of DOS 7.10 as the BOOTSECT.DOS file, then restore the boot sector content of XP, and then modify the boot.ini file, adding the line C:\="Microsoft Windows".

When booting, the boot selection menu appears, which proves that the XP-related startup files and sequence are not damaged, and selecting XP can also enter the system normally. However, if you select MS-DOS 7.10, the same phenomenon as described by the original poster occurs - "there is just a cursor at the top of the screen". May I ask, what steps are not done correctly if I want to install DOS in the presence of XP?

My problem is now solved. I did it again step by step on a new XP and succeeded. The only difference is that I originally used diskedit to handle the boot sector, and later simply used debug. It should be the same, and I checked the saved boot sector, which should be fine. I don't know the reason, but at least it shows that this step is correct.

As for the landlord's problem, I estimate it may be caused by the problem of the drive letter or/and whether it is an active partition. Because your DOS is installed on G: (for XP), and when you boot bootsect.dos from ntldr on C:, bootsect.dos cannot find IO.SYS on C:, so it crashes (but there should be a prompt按理说). Since I don't know when NTs starts assigning drive letters, I don't know whose C: bootsect.dos thinks it is after that.

Another possibility is that bootsect.dos successfully boots IO.SYS, but DOS thinks it doesn't boot from the active partition, so it crashes. Since I don't know the performance of DOS booting from a non-active partition, this is just a guess.

I think the latter possibility is relatively large because there is no prompt to crash. Also, what would be the performance if C: is not NTFS?

Can we still put bootsect.dos on G:, and change C:\BOOTSECT.DOS to G:\BOOTSECT.DOS? Because your DOS startup file is installed on G:, and after DOS starts, it will think that XP's G: is its C:?

Only C: can be used in boot.ini, and other drive letters are all invalid.

fujianabc: If I install DOS to drive D: and extract the boot sector of drive D into dos.bin, then place it on drive C, and then use c:\dos.bin="start dos", the NTLDR will definitely find the file. How to make it boot to drive D?

After NTLDR is successfully loaded, will it recognize drives like C and D?

Is it that NTFS format is not recognized? Try putting the file you want to boot in the first FAT32 partition and see if it works.

It's not unrecognizable. Installing XP on the C drive with NTFS can still boot.