What does it mean when you finalize a CD or DVD?

Question

I know you need to do it to play your CD/DVD on a different computer/TV, and that it means you can't add any more data, but what is it actually doing? What is your DVD burner doing to the CD/DVD when it finalizes it?

Answer 1

Finalization creates something like a Table of contents or Index that specifies where each track (CDs) or Title/Chapters (DVDs) can be found on the disc. This is the first thing a CD-ROM/DVD-ROM readers reads.

Answer 2

In simply words, the laser is leaving some kind of mark on the disc indicating that no more data could be added, or some formatting specs, for example, when you create Audio CD's from WAV files, finalization is automatically applied, because of its format, it means that all Digital Audio data insertion must be done once, and can not be done after that. When other Recorders read this mark, they noticed its finalization and alert that the disc cannot be further writed.