dosbox it's dos doesn't accept "weird" characters in filenames.
Try booting a dos version.

Some programs or games use those weried(special?) characters.
I thought that it should be supported for compatibility. (I also tried it in QEMU.)
Thanks for advice. I'll try to boot with DOS image in DOSBox later.

> I thought that it should be supported for compatibility.

It's quite hard to get a character mapping from dosbox (DOS)
to the host OS. Especially when it comes to multi-platform.

You don't need to worry about character mapping.
Just hit left-alt key, then you can use korean alphabets directly. (if you want to go back to english layout, hit left+alt again.)

wd means when it comes to files on the os.

Ah.. I understood.
I often don't read other's words carefully.