There are several ways to write data to a CD-R or CD-RW disc. Not all CD writers support all of these methods, but any method that a drive does support can be used to write to either a CD-R or CD-RW disc in that drive:
Disc-at-Once (DAO) recording writes the entire CD in one pass. The entire write must be completed without interruption. Once the write completes, no further data can be written to that disc. DAO recording can be used to write a single track (typical when creating a data disc) or multiple tracks (typical when creating an audio disc).
Track-at-Once (TAO) recording allows writing in multiple passes, as many as 99 tracks on a disc. Each track must be at least 300 blocks long, which translates to 600 KB for a typical data CD. TAO recording consumes 150 blocks in overhead for run-in, run-out, pregap, and linking. Also, because the LASER must be stopped and restarted for each track, there is at least one empty run-out block following each track and one empty run-in block preceding each new track. If the drive and burning software handle TAO recording properly, there will ordinarily be only one pair of run-out/run-in blocks between tracks. These blocks will be empty and therefore silent and ordinarily unnoticeable.
Some combinations of drives and software handle TAO imperfectly, placing garbage data in the run-out/run-in interstices that results in audible pops on audio CDs. Also, some drive/software combinations ...