INT 15 - Compaq Contura 486 and "Alladin" 08/05/93 ROMs - ???
        AX = 4605h
Return: CF clear if successful
        CF set on error (not supported)
            AH = 86h (unsupported function)
Note:   this function is a NOP (other than clearing CF) in the 08/05/93 version
          of the Contura 486/486c/486cx and "Aladdin" ROM, and the 7/26/93
          LTE Lite 386 ROM

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