In MS-DOS you always do an INT 21h with the function in AH. 09h is print string pointed to by DX, $ terminated 4ch is terminate program, with error code in AL

In MS-DOS you always do an INT 21h with the function in AH. 09h is print string pointed to by DX, $ terminated 4ch is terminate program, with error code in AL So you could build hello.com in short order. In Linux, the function numbers are effectively random[1], I don't see how you could build a binary and save it without a lot more work. [1] https://chromium.googlesource.com/chromiumos/docs/+/master/constants/syscalls.md https://chromium.googlesource.com/chromiumos/docs/+/master/c...