China DOS Union

A boot disk can start the machine. Is that because a boot disk can be regarded as a simple operating system, and through this operating system you can operate the computer? Is that right?? What I want to know is: after booting from a boot disk, does it directly use the operating system on the boot disk in the floppy drive, or does it use the boot disk to bring out the DOS operating system on the hard disk and then use the operating system on the hard disk? Or does it copy some files from the boot disk to the hard disk, and then use the operating system on the hard disk to start the machine??

If it's the first case, then if the hard disk is removed, the machine can still start the same way, right? It's just that apart from drive A, there are no other drive letters. Is that how it is?

If it's the second or third case, then if the hard disk is broken, wouldn't that mean it can't boot?

Asking for advice!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

It's the first kind. Even without a hard disk it can still be operated, and when computers first appeared, there were no hard disks at all, and they also booted directly from floppy disks.