Before pressing the 'ON' button in the emulator for the first time, you must set up your virtual system. This is done from the View/Options menu selection. It is advisable to use the Browse buttons to select the location and names of the system files. Select the appropriate Monitor ROM for the processor you have selected for emulation. Be sure to set the correct diskette type for the operating system that you are planning to run. If you have the SWTPC version of the OS9 v 1.2 ROM available to you, you can run it on the emulator. The ROM image files are actually binary files with FLEX binary file images in them. This is the format that the assembler outputs as an executable file.