Answer
Either works — the shared folder can be hosted on a Linux server or on a Windows management server; for a Linux-hosted share, an SMB server needs to be installed and running so the folder can actually be shared out. Whichever OS hosts it, create the shared folder, then configure the File Reader with the fully qualified path to that share (including its archive subfolder) plus the necessary credentials. If the File Reader still isn't picking up files from the share after that, raise the File Reader's log level to debug and check the resulting logs for the specific reason it can't reach or read the folder.