Track-At-Once

This is the first option that was introduced when CD duplication software was first created. With this mode, each time a track is finished burning, the laser recording the information stops. When it stops, two run-out blocks of data are written. After that, one link block and four run-in blocks are written when the next track begins to record. With track-at-once, you may burn both data and audio on the same disc. These blocks in between tracks are not a problem when data is being read, but you may hear a click on some CD players when playing back audio. This is something that may cause you problems if you are having your disc mastered and duplicated or replicated at a professional facility. In that regard, track-at-once is best suited for CDs for personal enjoyment.

Disc-At-Once

This burn mode takes all of your data, be it audio data or regular data, and burns it all to disc in one big block. No gaps are added between tracks, the laser never stops burning the data to disc. This is a newer feature, which should be an option in most modern CD burning software. One option you have with disc-at-once mode, which is kind of interesting, is that you can place allows any amount of audio data (or no data at all) to be written in the “pre-gaps” between tracks. With this option, you can place track introductions between each song. This is cool, because you can create “hidden tracks” on the CD in the pre-gap areas, that are only accessible by rewinding backwards into the pre-gap area. This is the ideal choice for CD masters that will be going to a CD duplication or replication house.