China DOS Union

Hello everyone, I'm a newbie. I want to bring up an idea for everyone to discuss, and I hope everyone can join in! Thank you very much! I have an IBM 20G portable hard drive. I had this idea for a long time before: to put a system on the portable hard drive. Wouldn't that make the portable hard drive into a portable PC? And it's much smaller than a real PC. Very convenient to use! And also, it's really cool! But when I finally got a portable hard drive myself and wanted to turn this idea into reality, I found there were many problems that were hard to solve. I don't even know whether it's feasible! First, if I make the system under DOS, then I run into the problem of driving the portable hard drive under DOS. Some time ago I used the moderator's super boot disk, but duse didn't recognize it and couldn't find the USB device! Just now I saw that someone has already solved this problem, so I think before long I can make that part work too! But my question now is: can the Windows installer recognize USB devices? When I choose the installation path for the system, can there be a drive letter for the portable hard drive? If there is, then of course there is no problem. Assuming the system has already been successfully set up, then how do I make the computer boot from the portable hard drive? Do I just need to change the first boot device in the BIOS to usb-hdd? If so, wouldn't the portable hard drive become a super-small portable PC? Is my idea too naive? I'll try it out in detail soon. If any expert can give me a few pointers, I'd be extremely grateful!