 Strictly created ISO 9660 filenames can only contain up to 8 capital letters or digits, followed by a period and up to three more capital letters or digits.TRANS.TBL is simply a normal file in each directory, containing the extended versions of file names in that directory; a system reading the filesystem can then use the extended filenames (sometimes called "long filenames") instead of the ISO ones.The TRANS.TBL file is a plain ASCII text file.