This statement directs the simulator to open the file 'filename' in mode 'mode'. 'filename' is specified as a string. 'mode' is specified as a string and is the access mode with which the file is to be opened. It corresponds directly to the mode argument of the fopen function of the 'C' runtime library. Valid values for mode are: 'r' read 'w' write 'a' append A full description can be found in the fopen documentation.open filename, mode