File System

When creating a data disc, you are able to choose between differrent file systems for it, by selecting from the menu Disc → File system. In this part of the help file we will explain the main differences between them and when to use or avoid using each of them. For more information visit these Wikipedia articles: ISO 9660, Joliet and UDF. Another purpose of this topic is to avoid being technical and remain on the practical side of this selection.

As suggested in the menu, file systems can work supplementary to each other, or they can be used stand alone.

When you cannot change the file system

If you imported data from a disc you previously started, you cannot change the file system afterwards and have to use the existing file system. Otherwise it might happen that changes done to the layout of the disc are not visible in all applications.


ISO9660: This is the oldest format, used for discs and has many limitations. First and most of all it only supports Roman characters (ASCII). There are three different variations for ISO9660: Level 1 (8+3), Level 2 (31) and ISO9660::1999 (Unrestricted). The numbers within the parentheses, are the maximum characters allowed for each file's name. A more detailed explanation:

  • Level 1: File names are limited to eight characters with a three-character extension, using upper case letters, numbers and underscore only. The maximum depth of directories is eight.
  • Level 2: File names are not limited to 11 characters (the 8.3 format) but may be up to the maximum allowed by the 1 byte counter in the dir entry and the filename length byte counter. Typically, this is close to 180 characters, depending on how many extended attributes are present.
  • Level 3 (ISO9660::1999): Unrestricted.

Restrictions for all these levels are:

  • All levels restrict filenames to upper case letters, digits, underscores (“_”), and a dot.
  • File names shall not include spaces, start or end with the dot character, have more than one dot.
  • Directory names shall not use dots at all.
  • 4 (or 2) GB limit for file size.

Joliet: A file system, specified and endorsed by Microsoft, which bypasses most of restrictions above and accomplishes this by supplying an additional set of filenames, up to 64 Unicode characters in length. This means that you can use any language, for file names.

UDF (Universal Disk Format): The newest file system format available which continues to be updated. While DVD-Video media use UDF version 1.02, Blu-ray media use UDF 2.50 or UDF 2.60. CDBurnerXP will use version 1.02 for CDs as well. Notable features:

  • supports media and files up to 2TB size
  • file names may be as long as 255 bytes (that is, 254 8-bit or 127 16-bit Unicode characters)

Where to use them

Most (and new) DVD players “ignore” the ISO9660 altogether and read the UDF file system.
Most portable players, including car systems, use ISO9660 Level 2, while some of them can read Joliet.
If you want to use the disc you will burn in such a system, to be certain Read The Manual of the device. The devices shouldn't be confused by the use of other file systems, in addition to the one they can read.

In general, UDF is most comfortable to use because of the very few restrictions it imposes on your disc's file system structure and is compatible with a broad range of devices and software. Sometimes however, UDF might not be supported by a device (or for other purposes than DVD-Video), in this case you need to use ISO/Joliet.

Earlier versions of CDBurnerXP allowed you to create so called “bridged” file systems, where ISO/Joliet and UDF were combined. This is no longer possible with version 4.5, but it may be supported in the future again.