The file system consists of storage media and files stored in the storage media. The firewall can manage both the storage media and files stored in it.
USG series firewalls can perform the following operations to the files.

A file system manages th files and directories in the storages device. In the file system, users can créate, delete, modify, and rename a file or a directory, and view contents of a file. The concepts of storage device, file, and directory are as follows:
Storage device: hardware devices for storing files, for example, flash memory cards, hard disks, and external USB devices.
File: used by the system for storing and managing information.
Directory: a collction of files and the logical container of files.
File system – Web operations.
When managing firewall configuration files, click Select to view the saved configuration files on the device an delete, modify, or use a configuration file. You can also click Upload to Upload a new configuration file.

Example of backing Up and Restoring a configuration file – Web UI.

Regards!
