Wow that's cool. Not how I remember it either. Surely though, there has to be some level of interpretation by dos. How does it know to put "Hello world" on the screen for example as opposed to the speakers or serial port? Or is that what INT 21h does?
Baez I have not tried his program but I think the code on his first post is the raw binary for the program there is no need for an additional compiler, hex or otherwise. I think he wrote the assembly in a text editor and then used an assembler to "compile" it into just 25 bytes of machine code.