* ? < > " | \ are the illegal characters in LTFS. What that means is they are not supported in file or folder names or file extensions. PreRoll Post automatically changes these to legal characters (underscores) for the archiving process. Upon retrieval the characters are switched back and presented to the user as they first appeared. The end user will never see a difference, as long as the PreRoll Post database is maintained and files are recovered from the tapes using PreRoll Post.
To be software independent, we recommend resolving illegal characters prior to backing up files whenever practical.