Int 21 Fn 09  - DOS 1+ - Write String To Standard Output                   [D]

   AH = 09h
   DS:DX -> '$'-terminated string

Return: AL = 24h (the '$' terminating the string, despite official docs which
       state that nothing is returned) (at least DOS 3.3-5.0)

Notes:  Break are checked, and INT 23 is called if either pressed
   standard output is always the screen under DOS 1.x, but may be
     redirected under DOS 2+
   under the FlashTek X-32 DOS extender, the pointer is in DS:EDX

See Also: AH=02h,AH=06h"OUTPUT"