Classification of Optical Discs

Optical discs can be classified by data type stored on them:

• Data discs can contain files of any type: document files (.txt, .html, .doc, .odt, etc.), audio files (.mp3, .wma, .wav, etc.), video files (.avi, .mov, .mpeg, etc.), image files (.png, .jpg, .gif, etc.) and so on.

  Note: even if you create a disc containing only video files in such formats like .avi, .mp4 etc., it will be called a data disc. As many home DVD/BD players do not have the ability to play such video files, they are not considered to be video discs.

• Video discs contain both audio and video signals and have a specific folders structure. They store DVD or Blu-ray video of a special format supporting features such as menus, selectable subtitles, multiple camera angles and multiple audio tracks. Such discs can be played back in all home DVD/BD players.

• Audio CD discs are designed to be used in a consumer audio CD recorder, which use Serial Copy Management System (SCMS), an early form of Digital Rights Management (DRM). Audio tracks on such a disc have the .cda extension. Audio CD discs are formatted in tracks, and the track numbers, index points and CD time code are encoded into the lead-in of the audio CD disc, and these reference points are found throughout the audio CD sub-channel.

• Bootable discs are removable digital data storage media, from which a computer can load and run an operating system or utility program. Bootable disks are used for:

  • operating system installation,
  • data recovery,
  • data purging (removal of sensitive data from a system or storage device with the intent that the data can not be reconstructed by any known technique),
  • hardware or software troubleshooting,
  • customizing an operating environment,
  • software demonstration,
  • administrative access in case of lost password,
  • games;
  • etc.

  Floppy disks and CD-ROMs are the most common forms of media used, but other media, such as magnetic or paper tape drives, zip drives, and more recently USB flash drives can be used. The computer's BIOS must support booting from a certain device.

  A modern PC is configured to attempt to boot from various devices in a certain order. If your computer is not booting from the device you desire, such as the floppy drive, you may have to enter the BIOS setup function by pressing a special key when the computer is first turned on and then changing the boot order.