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Windows NT/2000/XP NTLDR
To multiboot OpenBSD and Windows NT/2000/XP, you can use NTLDR, the boot loader that NT uses. To multi-boot with NT, you need a copy of your OpenBSD Partition Boot Record (PBR). After running installboot, you can copy it to a file using dd(1), following a process similar to:
# dd if=/dev/rsd0a of=openbsd.pbr bs=512 count=1
Note: this is a really good time to remind you that blindly typing commands in you don't understand is a really bad idea. This line will not work directly on most computers. It is left to the reader to adapt it to their machine.
Now boot NT and put openbsd.pbr in C:. Add a line like this to the end of C:\BOOT.INI:
c:\openbsd.pbr="OpenBSD"
When you reboot, you should be able to select OpenBSD from the NT loader menu. There is much more information available about NTLDR at the NTLDR Hacking Guide.
On Windows XP you can also edit the boot information using the GUI; see the XP Boot.ini HOWTO.
Programs that do much of this for you are available, for example, BootPart. This program can be run from Windows NT/2000/XP, and will fetch the OpenBSD PBR, place it on your NT/2000/XP partition, and will add it to C:\BOOT.INI
Note: The Windows NT/2000/XP boot loader is only capable of booting OSs from the primary hard drive. You can not use it to load OpenBSD from the second drive on a system.
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