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Appendix
Disc-at-Once (DAO)
This mode is used when writing a complete disc in a single pass without pausing. Data
cannot be added later, even if the full capacity of the blank disc has not been used.
Note
The lead-in and lead-out areas signify the beginning and end points of a session. They are not
part of the data but contain information about the session itself. Basically, a session consists of a
lead-in, data, and a lead-out.
Track-at-Once (TAO)
This mode is used when writing data to a disc one track at a time. More tracks can be
added later if there is enough space left on the disc. This is why Track-at-Once mode
is sometimes referred to as Multisession.
Note
Only the first session of a multisession disc can be played back on a conventional audio CD
player. Single session discs can be played back completely.
Writing Modes
Data
Example: General CD-ROM
Session 1
Track 1
Any remaining space
cannot be used
0
Lead-in
Lead-out
Audio
Audio
Audio
Audio
Audio
Audio
Audio
Session 1
Example: Audio CD
0
Lead-in
Track 1 Track 2
Track 3
Track 4
Track 5
Track 6
Track 7
Any remaining space
cannot be used
Lead-out
0
Data
Track 1
Data
Track 2
Data
Track 3
Session 1
Session 2
Session 3
Any remaining space
can be used
Lead-in
Lead-out
/Lead-in
Lead-out
/Lead-in
Lead-out
