Why are all Knoppix distros ISO9660? Isn't UDF better? There is no 2GB file size limit in UDF 2.01 (or ealier versions for that matter). If most systems can't boot off of UDF, then you can make a hybrid like DVD video discs, but unlike a DVD video disc, instead of the ISO and the UDF file systems containing references to the same files, the ISO would only reference the files necesary for booting and the rest of the files plus all the files referenced in the ISO system would be referenced in the UDF file system.