Appendix

Writing Modes

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.

Example: General CD-ROM

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Data

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Track 1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Any remaining space

 

 

 

Session 1

 

 

 

 

 

 

 

 

 

cannot be used

 

 

 

 

 

 

 

 

 

 

Lead-in

Lead-out

Example: Audio CD

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Audio Audio Audio Audio Audio Audio Audio

Track 1 Track 2 Track 3 Track 4 Track 5 Track 6 Track 7

Any remaining space

cannot be used

Session 1

Lead-in

Lead-out

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.

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Data

 

 

 

Data

 

 

 

Data

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Track 1

 

 

 

 

Track 2

 

 

 

 

Track 3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Session 1

 

 

 

Session 2

 

 

 

Session 3

 

 

Any remaining space

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

can be used

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Lead-in

Lead-out

Lead-out

Lead-out

 

 

 

 

 

 

 

/Lead-in

 

/Lead-in

 

 

 

 

 

 

 

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.

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