DVD-RAM, it is playable in about 75% of conventional DVD players. The primary advantage of DVD-RW
over DVD-R is the ability to erase and rewrite to a DVD-RW disc. According to Pioneer, DVD-RW discs
may be written to about 1,000 times before needing replacement, making them comparable with the
CD-RW standard. DVD-RW discs are commonly used for volatile data, such as backups or collections of
files. They are also increasingly used for home DVD video recorders.
DVD-R DL (double layer)
DVD-R DL (Dual Layer) (Also Known as DVD-R9) is a derivative of the DVD-R format standard. DVD-R
DL discs employ two recordable dye layers, each capable of storing nearly the 4.7 GB of a single-layer
disc, almost doubling the total disc capacity to 8.54 GB. Discs can be read in many DVD devices (older
units are less compatible) and can only be written using DVD±RW DL burners.
DVD+R (R = Recordable once)
A DVD+R is a writable optical disc with 4.7 GB of storage capacity. The format was developed by a
coalition of corporations, known as the DVD+RW Alliance, in mid 2002. Since the DVD+R format is a
competing format to the DVD-R format, which is developed by the DVD Forum, it has not been
approved by the DVD Forum, which claims that the DVD+R format is not an official DVD format. The
DVD+R format is divergent from the DVD-R format. Hybrid drives that can handle both, often labeled
"DVD±RW", are very popular since there is not yet a single standard for recordable DVDs. There are a
number of significant technical differences between the dash and plus formats, and although most
consumers would not notice the difference, the plus format is considered by some to be better
engineered.
DVD+RW (RW = ReWritable)
A DVD+RW is a rewritable optical disc with equal storage capacity to a DVD+R, typically 4.7 GB
(interpreted as 4.7 · 109, actually 2295104 sectors of 2048 bytes each). The format was developed by
a coalition of corporations, known as the DVD+RW Alliance, in late 1997, although the standard was
abandoned until 2001, when it was heavily revised and the capacity increased from 2.8 GB to 4.7 GB.
Credit for developing the standard is often attributed unilaterally to Philips, one of the members of the
DVD+RW Alliance. Although DVD+RW has not yet been approved by the DVD Forum, the format is too
popular for manufacturers to ignore, and as such, DVD+RW discs are playable in 3/4 of today's DVD
players. Unlike the DVD-RW format, DVD+RW was made a standard earlier than DVD+R.
DVD+R DL (double layer)
DVD+R DL (Double Layer), also known as DVD+R9, is a derivative of the DVD+R format created by
the DVD+RW Alliance. Its use was first demonstrated in October 2003. DVD+R DL discs employ two
recordable dye layers, each capable of storing nearly the 4.7 GB of a single-layer disc, almost doubling
the total disc capacity to 8.55 GB. Discs can be read in many DVD devices (older units are less
compatible) and can only be created using DVD+RW DL and Super Multi drives. The latest DL drives
write double layer discs slower (2.4x to 8x) than single-layer media (8x-16x). A double layer rewritable
version called DVD+RW DL is also in development but is expected to be incompatible with existing DVD
devices.
DVD-RAM (random access rewritable)
DVD-RAM (DVD–Random Access Memory) is a disc specification presented in 1996 by the DVD Forum,
which specifies rewritable DVD-RAM media and the appropriate DVD writers. DVD-RAM media are used
in computers as well as camcorders and personal video recorders since 1998. You can identify a DVD-
RAM disc due to lots of little rectangles distributed on the surface of the data carrier. Compared with
other writeable DVDs, DVD-RAM is more closely related to hard disk technology, as it has concentric
tracks instead of one long spiral track. Unlike the competing formats DVD+R, DVD-R, DVD+RW and
DVD-RW, you do not need special DVD burning software to write or read DVD-RAMs on a computer.
DVD-RAMs can be accessed like a usual floppy disk or hard drive. DVD-RAM is more suited to data
backups and use in camcorders than DVD±RW. The advantages of DVD-RAM discs are the following:
long durability of minimum 30 years and they can be rewritten more than 100,000 times, and also the
fact that no DVD burning software required in computers as the discs can be used and accessed like a
removable hard disk.