How to create an operating system ISO file from scratch?

Question

Operating Systems

There is a simple assembler OS that just outputs HelloWorld. Compiled .asm to .bin. After that, I received an ISO image from this binary using the UltraISO program. Checked on VirtualBox everything works. However, I would like to understand exactly how to write such an ISO file from scratch, without third-party programs like UltraISO, which did something there, but what it did is not clear.

Answer 1

Learn the ISO file format and write your ISO generation program.