dvd+/- r 和dvd+/-rw 和dvd+/-r dl

DVD +/-R
size = 4.7 GB media (or 4,700,000,000 bytes) [in fact stores only 4.37 GB on PC]
video = 2 hours of DVD video
also known as DVD-5 (or we call it D5)
burning data on disc = write once (R stands for Recordable)
purpose = for storing data/video/files that cannot be erased

DVD +/-R DL
size = 8.5 GB media [in fact stores only 7.95 GB on PC]
video = 2 hours of DVD video or more (with other special features)
also known as DVD-9 (or we call it D9)
burning data on disc = write once (R stands for Recordable, DL stands for Dual Layer)
purpose = for storing data/video/files that cannot be erased

DVD +/-RW
size = 4.7GB same as DVD +/-R
video = 2 hours of DVD video
also known as DVD-5 (or we call it D5)
burning data on disc = rewriteable and can be erased (RW stands for ReWriteable)

The + (plus sign) for DVD+R or DVD+RW or DVD+R DL discs
are usually used in DVD players in the consumer AV market
These disc formats are supported by Philips, Sony, Hewlett-Packard, Dell, Ricoh, Yamaha and others.

The - (minus sign) for DVD-R or DVD-RW or DVD-R DL discs
are usually used in DVD writers/drives in the PC market
These disc formats are supported by Panasonic, Toshiba, Apple Computer, Hitachi, NEC, Pioneer, Samsung and Sharp.

reference :
What is DVD, DVD-R/RW, DVD+R/+RW, DVD-RAM, DVD+R DL?
DVD Formats Explained




### others pls do not copy my reply


2007-08-24 15:04:15 補充：
又有人話可以多次分批入資料 咁其實邊樣arm呢??! when recording a DVD (any type of blank disc), there are 2 ways to burn the data.

2007-08-24 15:04:32 補充：
a) without multi-sessionie. burn ALL data / everything at ONE time only and then finalize the disc. then no more data can be added afterwards

2007-08-24 15:04:53 補充：
b) with multi-sessionsie. burn data/files incrementally and leaving the disc "open" for subsequent burning, however, not every DVD disc can read this kind of multi-sessions data. for example, if recording DVD-video, the entire movie/film must be recorded using option (a) only.

2007-08-24 15:06:47 補充：
兩者的用途不同處是 : DVD+R is mainly for DVD VIDEO (to be played on DVD player appliance)DVD-R is mainly for computer data, software, program, etc....