Yamaha CRW8424SX Series Owner's Manual page 36

Session-at-Once (SAO)
This mode is used when writing each session in a single pass without pausing. More
sessions can be added later if there is enough space left on the disc.
Example: CD-Extra
Audio
Track 1
Session 1
n With CD-Extra, the audio is written in the first session and the data is written in the second.
A maximum of 99 tracks can be written.
Packet Writing
This mode is used when writing to a track of a disc using small blocks of data called
"packets," in a manner similar to a floppy disk. This mode is useful when making small
incremental backups of data. You will need to use software which specifically supports
packet writing, such as Adaptec' s DirectCD.
1 2 3 4
Packet
n Discs must be formatted before they can be used for packet writing. With CD-RW, erased data
can be overwritten until the disc is completely full.
With CD-R, the space used by the erased data cannot be reused and is "masked" so that it is
no longer visible. This can be done up to 100 times.
Audio Audio
Track 2 Track 3
. .
5 6 7 8
28
Data
Track 4
Session 2
. . . . . .
Same as writing to floppy or hard disk
Appendix
. . . .