CDFS stands for Compact Disk File System. It is a 32-bit file system. CDFS replaced the older 16-bit Microsoft CD-ROM Extension around the time of the introduction of Windows 95. The purpose of CDFS is to provide a file system accessible by a multiple operating systems. Data can be written to a CD in Mode 1 or Mode 2. Mode 1 and mode 2 form 1 are designed for writing data CD's. Mode 2 Form 2 is designed for media such as audio and video CDs. It provides less error correction and thus allows for 14% more data to be written to the disk. The reason for this is that small losses in information in a media file may not be notices whereas they would likely be catastrophic in stored data files.
The first 15 sectors on a CD are often used for boot information if a CD is bootable. The section following that is reserved for the volume descriptor. Multiple descriptors or duplicate descriptors may be written in this section so that if one is not understood it can be skipped and the next one can be used. This helps with multiplatform compatibility support as well as reliability.
In the latest version of CDFS (ISO 9660:1999) the maximum path length was increased to 207 characters. The restriction of the maximum nested folder depth of 8 was lifted. Also the restrictions of the use of the dot character in a file name were eliminated.