: .EXIT ax &h4c00 | # mov &h21 int ;
: d" begin in@ dup [ in@ " lit ] != while outb! repeat drop ;

cs push \ copy code segment to data segment
ds pop

tell 1 + dx 0 # mov
ah 9 # movb
&h21 int

0 .EXIT

tell 
d" Hello World!$"
&h100 + swap seek outw!