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ABC's Of
DVD Drive Abbreviations
by Jason Kohrs
The number of different formats available in DVD drives can be confusing
to anyone in the market for one. The list is much longer, but to address
a few of the common formats, we have DVD-ROM, DVD-R, DVD-RW, DVD+R,
DVD+RW, DVD-RAM ,DVD+R DL and DVD±RW. Wow! This list of common formats
is long enough, no wonder it's confusing!
What's with all the Formats?!
The reason for various recordable DVD formats is that no one group owns
the technology and different groups have chosen to support one
technology over another. There is no industrial standard for
manufacturers to reference, so for the time being consumers will have a
few choices.
The first thing to address is DVD itself, which stands for Digital
Versatile Disc. Some may argue that the V stands for Video, but with the
capability to store video, audio, and data files, Versatile is
definitely the keyword.
Start with the Basics
A DVD-ROM drive is the only one we will address that does not record.
ROM stands for Read Only Memory, and refers to the typical drive that
can merely read DVDs, as well as CDs (all DVD drives can read CDs). The
Lite-On LTD-163-DO-R has attributes representative of your typical
DVD-ROM drive, and features a maximum DVD read speed of 16x and a
maximum CD read speed of 48x.
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Before getting into the different recordable formats, let's address the
basics of what the R and RW stand for, regardless of whether there is a
+ or - in the middle. R stands for Recordable, which indicates that the
disk may be recorded to only once. RW stands for ReWritable, which
indicates that the disc may be recorded to more than once, and are
generally rated for 1000 rewrites under good conditions.
The DVD-R/-RW format was developed by Pioneer, and was the first format
compatible with stand alone DVD players. The group that promotes the
technology calls itself the DVD Forum, which is "an international
association of hardware manufacturers, software firms, content
providers, and other users" with notable members such as Hitachi,
Samsung, and Toshiba. The DVD-R/-RW format is based on CD-RW technology
and uses a similar approach to burning discs.
The DVD+R/+RW format is a newer format, also based on CD-RW technology,
and compatible with a large percentage of stand alone DVD players. The
+R/+RW technology is not supported by the DVD Forum, and its main
backing comes from a group called the DVD+RW Alliance. The Alliance "is
a voluntary group of industry-leading personal computing manufacturers,
optical storage and electronics manufacturers" with members such as
Dell, Hewlett Packard, Sony, and Phillips Electronics.
The DVD-RAM format is based on PD-RW (Phase-Differential) drives, and
actually uses a cartridge to hold the media (just like its PD-RW
predecessor). Some DVD-RAM cartridges are double sided, making them
ideal for companies to use as system backup, hence DVD-RAM is usually
found only in commercial applications, and most end-users won't ever
need to use or see this type of drive. The DVD-RAM standard is also
supported by the DVD Forum just like the DVD-R/RW format. However,
because of its use of a cartridge (limiting it's compatibility), and the
scarcity and price of the media used, DVD-RAM is a distant third when
compared to the DVD+R/+RW and DVD-R/-RW technology.
The +R/+RW and -R/-RW formats are similar, and the main difference DVD+R
technology has is the ability to record to multiple layers (with its new
DVD+R DL format), where DVD-R can only record to one layer (not all +R
drives are capable of dual layer burning, but no -R drives are). The
Plextor PX-504U is an example of an external DVD+R/+RW drive capable of
recording single layer discs in the +R/+RW format, but also able to read
discs recorded by a DVD-R drive.
What is DVD±RW?
DVD±RW is not actually a separate format, but the designation given to
drives capable of both -R/-RW and +R/+RW operation. This type of drive
is typically called a "Dual Drive" (not to be confused with a "Double
Layer" drive) since it can write to both the +R/+RW and -R/-RW formats.
The Samsung TS-H552 is a DVD±RW drive capable of reading and writing
every format discussed so far, and then some. It takes advantage of
DVD+R DL (Double Layer) technology available with the +R format,
allowing the appropriate media to store virtually double the 4.37 GB
capacity of a typical single layer disc.
The other main thing to consider with DVD burners is selecting the
correct media. Media for DVD-R, DVD-RW, DVD+R and DVD+RW media may all
look the same, but they are slightly different in order to match the
specific recording formats. The price of media for either format is
generally the same, with RW media costing a good deal more than R media
of either format. Double Layer media is even more expensive, and is the
only way for an owner of DVD+R DL drive to take advantage of the
tremendous capacity increase. As the amount of Double Layer drives
increase in the market, the price of the DVD+R DL media is expected to
fall with increased production of the media. DVD Burners (as these drive
are often referred to) can be picky about the media supported, so be
sure to choose your media wisely.
DVD in a Nutshell
DVD-ROM : Reads DVD discs
DVD+R : Writes to DVD+R media (will also typically write to CD-R and
CD-RW media)
DVD+RW : Writes to DVD+RW media (will also typically write to DVD+R,
CD-R and CD-RW media)
DVD+R DL : Writes to DVD+R DL (Double Layer) media (will also typically
write to DVD+R, DVD+RW, CD-R and CD-RW media; many Double Layer drives
are ALSO dual drives - that is, able to write to BOTH +R/RW and -R/RW
media)
DVD-RAM : Writes to DVD-RAM cartridges (not in wide use on consumer
market - mainly a business format; can also read PD-RW discs. Will not
usually be able to write to any other format including CD-R or CD-RW)
DVD-R : Writes to DVD-R media (will also typically write to CD-R and
CD-RW media)
DVD-RW : Writes to DVD-RW media (will also typically write to DVD-R,
CD-R and CD-RW media)
DVD±RW : Writes to DVD-RW and DVD+RW media (will also typically write
to DVD-R, DVD+R, CD-R and CD-RW media; typically called "Dual Drives"
since it can burn to two different DVD formats)
Final Words
This article took a look at the more common formats of DVD drives in
order to shed some light on all the choices available. The differences
between them all may be subtle, but the compatibility issues can be
quite frustrating. The simple answer to anyone considering a drive is to
forget about + and - by themselves, and shoot for universal
compatibility with a good DVD±RW with DVD+R DL support.
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