Answer:
Live file system
Step-by-step explanation:
The live file system allows you to continue adding files to CD or DVD disc after an initial burn as long as there is enough space left on the disc.
In an attempt to burn files on a CD or DVD disc, Windows will prompt you if you want the live file system or the other (which is mastered disc format). Once you select the live file system, you can then keep adding files over and over until there is not enough space on the disc.
Note that Windows might not display the prompt as "live file system". It could be represented in some other ways like: "Like a USB flash drive". But then going through the prompt will tell you which is which.