Hello, To write or read text files on to the Rabbit modules you need serial flash, NAND flash or SD card on the module. On RCM4300 it has Micro SD card facility.
Another thing is to write or read text files on the card , you need to create fat file system on the Micro SD card. Then you can able to display all the files and folders
Under Dynamic C 10.72 at below path
there are some sample applications regarding fat file system, go through these sample apps, it may helpful.