Int 21H, AH=5BH

3 and higher

CREATE NEW FILE

	AH = 5Bh
CX = file attribute (see #01420 at AX=4301h)
DS:DX -> ASCIZ filename

CF clear if successful
    AX = file handle opened for read/write in compatibility mode
CF set on error
    AX = error code (03h,04h,05h,50h) (see #01680)

unlike AH=3Ch, this function will fail if the specified file exists
  rather than truncating it; this permits its use in creating semaphore
  files because it is an atomic "test and set" operation
under the FlashTek X-32 DOS extender, the filename pointer is in DS:EDX

AH=3Ch,AH=5Ah

Text based on Ralf Brown Interrupt List Release 61