pag +R you can add data files after initial burning, given the fact that you didn't fill the DVD up on initial burning. oh yah, hindi nababasa ng -R DVD roms ang +R DVD roms.
pwede rin sa -R ang multisession burning, nasa feature na yan ng burner or software.
dual layer or DVD9 means the disc can hold around 9GB of data, while single layer or DVD5 can hold around 5GB.