The -rw flag uses floppy-image in read-write mode, meaning that no save or save-diff-file command to the associated image object need to be used in order to save data written by the target software.
To access a host floppy device on Linux (assuming the floppy device object is called flp0):
simics> flp0.insert-floppy A /dev/fd0
To use a floppy image file:
simics> flp0.insert-floppy A floppy.img
To boot directly from the floppy on a simulated x86 architecture, select the "A" drive to be the boot device:
simics> <motherboard_x58_ich10>.cmos-boot-dev A