If you want to create a data CD that consists of several sessions, we advise that you create a Multisession CD. Every complete write process with Nero on a CD, from inserting the CD you want to write to the CD being ejected, generates a session on the CD. A session in turn contains one or more tracks. All CDs with several sessions are 'Multisession CDs'.
There are basically two types of Multisession CD: