China DOS Union

I have a question: where on the hard disk are these boot systems installed?
Grub
Ntloader
Win98/Dos
Sun Solaris For X86
BeOS

I know that when installing linux, it prompts you to install Grub/lilo to hda or hdaX, that is, to the MBR of the whole hard disk or to a certain partition. But aren't Ntloader and Win98/Dos also installed to the MBR? If so, wouldn't they get overwritten? Could someone explain more clearly exactly which part of the hard disk these systems' boot systems are installed to?
Because I want to install multiple systems recently, and I still haven't decided on the boot issue, so please advise?

Stored in the system

The following is quoted from disk's post at 2003-11-6 18:06:54:
Stored in the system

Hey, man, do you actually understand this or not? If you do, then please explain it more clearly. If you don't, then please don't make irrelevant sarcastic remarks here.

Do you mean the DOS boot sector or the boot files? Why are you putting it so vaguely?

I guess it should count as the boot sector.
What I really want to know is: when the system starts up, from the very beginning when it starts reading the hard disk up until entering the DOS prompt, which sectors and which files are read or written in this process, and what exactly is the whole flow?

Grub/Lilo: generally the boot information is placed in the MBR, and then it calls the corresponding file in a specified area of the disk (for example stage2);

NTLDR: generally the boot information is placed in the MBR, and then it calls the NTLDR file to display the multi-system boot menu;

DOS (note: no Win98, because it is not an operating system but a GUI platform under DOS): the boot information is generally placed in the Boot Sector of a certain partition, or the boot sector file is called through boot managers such as Grub/Lilo/NTLDR, and then it automatically calls the boot files on C:\, such as IO.SYS/IBMBIO.COM/KERNEL.SYS, etc.

Linux/FreeBSD, etc.: their kernels are called directly by boot managers such as Grub/Lilo to start them;

BeOS PE edition: its kernel can be called directly under DOS, similar to BasicLinux, etc.