Live File System is the term Microsoft uses to describe the packet writing method of creating discs in Windows Vista and later, which allows writeable optical media to act like mass storage by replicating its file operations.
Files can be added incrementally to the media, as well as modified, moved and deleted.
Windows 2000 for example only supports the original UDF 1.50 variation and not the Virtual Allocation Table build for remapped physical blocks; something not all optical drive units fully implement either.
[2] If users create DVD/CDs in Windows Vista using UDF 2.50, these may not be readable on other systems, including Windows XP and older (pre-Mac OS 10.5) Apple systems unless a third-party UDF reader driver is installed.
To ensure compatibility of disks created on Windows Vista, UDF 2.01 or lower should be selected.