One final issue involves what happens to files on the different storage media when you reboot, do a full reset or totally reflash your Z.
Simply powering off or rebooting your Z should not affect any of the files in writable flash or RAM, or on removable media such as CF or SD cards.
Doing a full reset will delete all data installed in RAM, but will preserve all of writable flash and all removable media.
Finally, reflashing your Z with another OZ image will delete all data in both writable flash and RAM, but once again will preserve all data on removable media such as CF and SD cards.