Three
Formats (or four, or five?)
There are currently three
major formats, breaking down into five when write-once and rewritable media
support is considered.
DVD+RW (rewritable)
DVD+R (write once)
The “plus” is the new
kid on the block, competing with DVD-R/RW (the “dash”) for market domination.
There are several major benefits, and seemingly one small drawback – the “plus”
discs are reported to be somewhat less backward with other drives than the
“dash” format discs – specifically the –R, write-once media.
As of this writing the
+R write-once only a specification for a future “extension” of the +RW format
– no available drives seem to support it, and no media is available. Support
for write-once media by virtually all manufacturers is expected sometime in
2002, its presumed benefit being lower disc cost.
DVD+RW drives are just
starting to appear on the market from the manufacturers promoting this technology,
HP, Philips and Sony.
DVD-RW (rewritable)
DVD-R (write-once)
These are two iterations
of the same format – one rewritable, one not – and drives are available both
ways as well. DVD-RW is the format used by the Pioneer drive in the new Apple
G4 and high end Compaq multimedia workstations, apparently for one good reason
-- it produces the most compatible DVDs for video playback possible. With
a push toward convergence, desktop video is expected to be the “killer app”
of DVD recordable technology.
The major drawback for
the –R/-RW format is its limited utility as a PC file storage device. Certainly
over 4 Gigs of data files, such as a backup archive, may be stored and retrieved
on a DVD-R or –RW disc – this much is true. But both DVD-RAM and DVD+RW offer
significantly higher performance and greater protection from write errors,
as well as a much broader range of features enhancing both usability and utility
for using the drive as a PC storage device. DVD-R/RWs forte is video -- period.
DVD-RAM
This is the original format
for DVD recording technology, based on the format used for older magneto-optical
technology. With rapid file access and defect management built in, DVD-RAM
(like DVD+RW) has some distinct advantages over DVD-R and -RW when it comes
to data storage duties (while the “plus” drives claim to do everything DVD-RAM
does and more – save for offering –R format support).
The downside to this format
is that playback support for a disc made on DVD-RAM is extremely limited –
but not unavailable. Some existing PCs’ DVD drives will read the discs, and
at least one currently available DVD Video player (from Panasonic) offers
DVD-RAM support, with others sure to follow from manufacturers supporting
the format, such as Hitachi, and Toshiba.
Technically, DVD-RAM offers
substantial benefits over –RW for use in computer data storage, and may evolve
to offer benefits over DVD+RW. However, the lack of backward compatibility
with existing DVD-ROM and video drives seems likely to handicap the success
of this format. In response, many DVD-RAM manufacturers are offering, or planning
to offer, DVD-R support for video. This is an important point.
If DVD-RAM is an ideal
format for use as a PC data storage device – and the same drive can produce
the widely readable DVD-R discs for video – is there any reason to consider
the (currently) more expensive (and less mature) DVD+RW? The answer to that
question might best be considered in context of how many other +RW format
devices you may come into contact with. Remember, this format war is going
on in the home entertainment arena as well, and a major victory there may
have an influence on what sort of drive will be found in PCs in the coming
years.
Which to Choose?
If DVD-RAM drives were
not beginning to offer support for DVD-R, DVD+RW would be seem the clear preference
for most users, save for those solely interested in desktop video production.
DVD-R (and –RW) seems
best considered an interim technology, despite its early adoption by OEMs
and rapid proliferation, due to its broad compatibility and suitability for
bringing video production to the home desktop.
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