The following configuration options are available on the Multisession tab in the Multises-sion area:Р”В«urns the selected compilation in one session to the disc. Multisession discs are particularly suitable for backing up important files burned on a regular basis. If you disable the Finalize disc check box on the Burn tab, you can always burn additional sessions on the disc, but then only the last session will be visible and you will only be able to access data from the final session. In this case Nero Burning ROM automatically verifies whether the correct multisession disc has been inserted for continuation. The files in the previous sessions are retained and continue to take up space. You must define which session is being im-ported at the start of the burn process. the table of contents for the imported session is copied to the table of contents for the current session. If a multisession disc is being continued, Nero Burning ROM automatically sets a cross ref-erence to the imported session, i.e. This information is used when continuing the multisession disc. If a new multisession disc is being started, Nero Burning ROM also saves (if possible) the point of origin for the files. Audio CDs, are burned in a single session. Discs without the multisession option, e.g. A session is a self-contained data area that is burned using a single process, and consists of a lead-in (with the table of contents), one or more tracks, and a lead-out. Multi-session discs can be burned in multiple sessions until you have reached the maximum disc capacity. The Multisession tab provides the option to create multisession discs for data discs. On the other hand if you do not want to add more data into this disk ,then not select this option. If you have some data (Word,PowerPoint and Excel ) and picture say the size is 100 Mb so when you burn into CD Disk ,you will have 600 MB available to add more data by selecting the option of Multisession in Nero. Main idea is about the CD/DVD disk capacity I will give you simple explanation as follow

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