CDfs is a file system for Linux systems that `exports' all tracks and boot images on a CD as normal files. These files can then be mounted (e.g. for ISO and boot images), copied, played (audio tracks).
cdrecord-filters is a patch for cdrecord to make it able to accept user-created modules that can create tracks for cdrecord on-the-fly. One module that allows you to read mp3s and write them as audio tracks is provided in the package.
Cdctl is a program similar to eject which can eject your CD-ROM/DVD drive. Cdctl provides a user interface to the 2.2 kernel's uniform cdrom driver's ioctl calls, and most 2.0 cdrom drivers (ide-cd and scsi).