printf without '\n'

Newbie simple question:

With a code like this:

.section .data
MSG:
	.ascii "Hello\0"
.section .text
	.globl _start
_start:
	pushl %ebp
	movl %esp, %ebp

	pushl $MSG
	call printf

        movl %ebp, %esp
        popl %ebp

	movl $1, %eax
	xorl %ebx, %ebx
	int $0x80

I compiled it with:
as code.s -o code.o; ld --dynamic-linker /lib/ld-linux.so.2 -lc \
	test.o -o test

With that ascii string, nothing is printed but when I use "Hello\n\0" it
works fine. 

What is the reason for not printing the string if there isn't a '\n' in
it?

I something related with the buffered (by lines) IO?

Why with a C program it does not happend.

Thanks in advance.