File System Creation

hi support,
I am now developing an application in digi connectem using NET+works 6.3.In this application i
want to create a file system.i am using ur flash0_init() from ur sample program and create some directories
using NAFScreate_dir.Is it needed to create these directories everytime or only in the first time ?.or only
flash0_init()with #define ERASE_FLASH0
0 is needed…please give me the details