CD-R technology
  Limitations.
    Constant linear speed requires data to be delivered at constant rate 
    when burning.
       When data cannot be delivered in time, it is called buffer under-run 
       and trashes the disk.

    VTOC - volume table of contents - lists the files and their sectors.
      Found at the beginning of the track (1st sector).

      Original CD-R always and only looked in 1st sector.
        One reason why older drives could not read newer multi-session 
        discs.

      VTOC had to be written first and had to be complete.

      Thus the write once read many (Worm) nature of a CD.

  Level 3 allows the original VTOC to be invalidated and rewritten.

    The new VTOC will be stored elsewhere on the disk.
      Location of new VTOC stored in reserved location in old VTOC.
 
    The OS will search for the most current VTOC.

    This allows the user to add new files or hide old files (delete).

    Storage for deleted files not recoverable.

    Rewriting VTOC limited to 99 times and takes at least 1 sector.
      VTOC daisy-chained.

      Keep in mind all of the VTOC (1 or more sectors) must be rewritten 
        each time.
     
      Also, old copy of changed file still on the disc.