How to boot pure DOS under WinNT/2K/XP
Now some net friends have started installing WinNT/2K and even XP. But after they boot these operating systems, they find that many DOS programs can no longer run, and pure DOS can no longer be booted either. What's going on here?
As everyone knows, WinNT/2K/XP has something called the "command prompt." On the surface it looks similar to the MS-DOS box in Win3.x/9x. However, they are completely different. Win3.x/9x are large protected-mode interface enhancement programs running under MS-DOS, while WinNT/2K/XP are independent operating systems based on OS/2 and NT components, so there is an essential difference between them. By the same token, the MS-DOS provided in Win3.x/9x is real DOS, while the "command prompt" in WinNT/2K/XP is merely a "DOS virtual machine." Since it is virtual, the effect is naturally not as good as the real thing. Therefore, when this "virtual DOS" cannot run DOS programs properly, the only way is to use real DOS (including the MS-DOS 7.x that comes with Win9x) to run them.
Since WinNT/2K/XP do not come with DOS, if you want to boot from the hard disk into pure DOS after installing these operating systems, you can only use dual boot. Many users know that when WinNT/2K/XP start up, a menu often appears from which you can choose which operating system to boot. However, sometimes there is no "DOS" option in this menu, and sometimes this boot menu does not appear at all when booting (if you choose to keep the original operating system when installing WinNT/2K/XP, then the boot menu of WinNT/2K/XP will include the original operating system as an option). So what should be done? Below is an introduction to the method of installing DOS after WinNT/2K/XP have already been installed.
Booting DOS requires the DOS system boot sector and startup files. And the key to installing DOS after WinNT/2K/XP have been installed is to create them. Some of you may ask: after WinNT/2K/XP are installed, hasn't the content in the master boot sector already been replaced with non-DOS code? Why can DOS still be started through the boot menu mentioned above? This is because if DOS (including the MS-DOS 7.x that comes with Win9x) was once installed on the system, WinNT/2K/XP will automatically create a BOOTSECT.DOS file in the primary boot partition (usually drive C), and this file preserves the DOS boot information. After choosing to boot DOS in the boot menu, WinNT/2K/XP use this file to make DOS start. Therefore, if the BOOTSECT.DOS file already exists in C:\（ (that is, the primary boot partition), there is no need to create it manually. You can directly copy DOS files such as IO.SYS, MSDOS.SYS, and COMMAND.COM (for example from MS-DOS 7.10) to C:\ (it is best not to transfer the system with the SYS command; see the next paragraph for details), and then modify the BOOT.INI file as described below.
As for DOS system startup files, everyone knows that the SYS command that comes with DOS can be used to transfer them. However, if you do this directly, then only DOS will boot, and the boot information of WinNT/2K/XP will be overwritten, making them unable to boot. In order to make both DOS and WinNT/2K/XP boot, there are several methods. You can use a very practical tool called BOOTPART, which can be found in this site's "system tools." Its functions are very powerful; for example, it can write information for a specified system into the boot sector, including DOS6, DOS7 (Win9x), and WinNT (/2K/XP). For example, if you want to write the boot information of MS-DOS 7.10 (Win98) into drive C, you can use the command BOOTPART WIN98 BOOT:C:. Therefore, the specific method is: first use the SYS command (such as SYS C
to transfer the DOS system files to drive C, then save the information in the primary boot sector at that time (that is, the DOS boot information) into the file C:\BOOTSECT.DOS. This can easily be done with a small tool called SRC Tools in this site's "disk tools." SRCBOOT, SRCMBR, and SRCFAT are commands for saving, backing up, and comparing the BOOT, MBR, and FAT respectively. The specific usage of the SRCTools collection can be seen in a special article under the "DOS articles" section. For example, SRCBOOT C: C:\BOOTSECT.DOS /S can save the boot sector of drive C into the file C:\BOOTSECT.DOS. At this point the BOOTSECT.DOS file has been successfully created. Next is restoring the boot information of WinNT/2K/XP, which can be done with the BOOTPART tool mentioned above, such as BOOTPART WINNT BOOT:C:. After that, just perform the BOOT.INI modification described below.
Another method is to first save the boot information of WinNT/2K/XP into a file, then create the DOS system startup files and boot information separately, then use the SRC Tools mentioned above to save the DOS boot information into the file C:\BOOTSECT.DOS, and finally restore the WinNT/2K/XP boot information saved in the file back into the boot sector. The specific process for creating the DOS system startup files and boot information can be seen in the method above, while saving and restoring the WinNT/2K/XP boot sector can both be done with SRC Tools commands. For example, you can execute SRCBOOT C: C:\NTBOOT.DAT /S and SRCBOOT C: C:\NTBOOT.DAT /R respectively to complete it (/S means save, /R means restore, and NTBOOT.DAT is only a temporary file used when saving and restoring the WinNT/2K/XP boot information, and can be deleted after completion), and then carry out the operation below.
Finally, you can start making the dual-boot menu. The boot menu of WinNT/2K/XP is stored in the BOOT.INI file under the root folder of the primary boot partition (usually C:\BOOT.INI). The method is to first remove the read-only, hidden, and system attributes of the C:\BOOT.INI file (for example with the ATTRIB command that comes with DOS, or an enhanced ATTRIB command, etc.), then open the C:\BOOT.INI file with a text editor (such as the EDIT that comes with DOS), and under the entry in the file add a line: C:\="MS-DOS". After finishing, save the file and restore its various attributes, then restart the system,
it should: show a boot menu, with an "MS-DOS" item in it.
Result.......... mine is C:\
