I would like to find out what file system is being used so that I can try and find a program that will let my PC see the contents on an Xbox drive, for the purpose of data recovery. Has anyone had any luck doing that? I am going to try EaseUS Data Recovery first, but I don't think it will let me add or modify files, just recover them to the PC.
They use a custom file system called FATX. Windows (at least historically) has not supported reading these, but there is limited support found on Linux and MacOS.
If you're just looking to make a full disk backup, taking a full disk image backup is a safer bet than attempting to read/write on the file system level.