The basic standard for recording computer data files onto Compact Disc. ISO 9660 allows only for upper case 8.3 type filenames, using the characters A to Z, _ (underscore) and - (minus or hyphen).
Because of the limitations of ISO 9660, various extensions to the standard exist to permit the use of long filenames and more characters, but these extensions are not compatible across the various computer platforms (Microsoft, GNU/Linux, UNIX, and Macintosh).
Consequently, if you want to create a disc that can be read by all current computer systems, you must stick to plain old ISO 9660.