CDfs is a virtual Linux file system that enables mounting, accessing, copying and playing of voice and data on a CD track by exporting the tracks and boot images as normal files. It helps unlock information in old ISO images. It can help access older files with the same name written on a multisession CD which would otherwise not be accessible in case of ISO9660 file system. It supports a few track types in the form of Red Book audio, White book video and Yellow book data. It is usually not supplied with the Linux Kernel, but is available freely.