Int 21 Fn 2D  - Dos 1+ - Set System Time                                   [D]

   AH = 2Dh
   CH = hour
   CL = minute
   DH = second
   DL = 1/100 seconds

Return: AL = result
       00h successful
       FFh invalid time, system time unchanged

Note:  DOS 3.3+ also sets CMOS clock

See Also: AH=2Bh"DOS",AH=2Ch,INT 1A/AH=01h,INT 1A/AH=03h,INT 1A/AH=FFh"AT&T"