This module gives you a way to easily download a compressed archive file of any files which have changed since the installation - ie files that have been uploaded by users. By default, it is assumed that these will all reside in the site's "files" directory but you can specify other directories to back up as well.
It is intended to complement the Backup and Migrate module, which backs up the database tables. By using the two modules it is hoped that you can easily implement a good backup strategy.
The module does not have a restore facility - but you can easily restore backed up files using an ftp client or the file browser in the IMCE module
The latest version of the DB Maintenance module (currently in beta) also gives you the ability to backup files. Some users might find this a better solution as database and file backups are handled in a single package (as well as database optimization).
DB Maintenance makes calls to the tar and mysqldump commands to achieve its backups. Backup Files uses a different technique - it uses the PEAR package and the Archive_Tar package which, if they are not present on your system, can be downloaded and installed with the module.
So, if your host does not allow access to the tar command Backup Files should still do the job (and Backup Migrate will back up your database tables similarly).