section .text
    global _start       ;must be declared for using gcc
_start:                     ;tell linker entry point
    mov edx, len    ;message length
    mov ecx, msg    ;message to write
    mov ebx, 1      ;file descriptor (stdout)
    mov eax, 4      ;system call number (sys_write)
    int 0x80        ;call kernel

    mov eax, 1      ;system call number (sys_exit)
    int 0x80        ;call kernel

    mov eax, 4
    mov ebx, 1
    mov ecx, msg2
    mov edx, len2
    int 0x80

    mov eax, 1
    int 0x80

    jmp $

section .data

msg db  'Hello, world!',0x0 ;our dear string
len equ $ - msg         ;length of our dear string
msg2 db 'seems like KatauOS just executed this ELF-file!!',0x0
len2 equ $ - msg2