The next option to consider when choosing recordable CD-R/RWs is the capacity of
the media you use. CD-Rs and CD-RWs are easily available in 650MB/74min and 700MB/80min sizes,
though larger capacities can be found.
Consistent with the speed rule listed above, the newer the drive, the less
likely it is to have difficulties with higher capacity media. Older drives may
have issues because of the increased density of the data tracks in the higher
capacity disks. Any writer made within the last 3-4 years should be fine with at
least the 650 and 700MB media.
The last possible issue is the
colour of the CD-R. Now this was a really hot topic a few years ago when CD
writers were coming onto the mass-market, with heavy debates on all sides. The
issue is which combination of dye and reflective material provides the best
compatibility, and which dye gives CD-R media the most longevity?
The colour of the bottom of a
CD-R disk is a combination of the dye type and the reflective layer of metal.
For example, the combination of Cyanine (one of the most popular dyes) and a
silver reflective layer results in a blue/green sheen. Older writers were noted for liking some colour combinations better than
others, resulting in a lot of wasted CDs and frustration.
any newer CD-RW drive should not
be particularly fussy when it comes to the colour of the disks you
feed it, but the best method here is to visit the manufacturer's website and
check their list of compatible media. Come to think of it, this is the best
method for dealing with all the issues we've just listed.
The subject of
data-fastness and longevity of CD-media is still being debated, and likely will be for
a while. Artificial 'rapid-aging' tests on various CD-R media types have
shown that gold reflective disks seem to hold readable data for longer than
other colours of CD. Some estimates give as long as a hundred years before the dye
becomes unreadable, even the cheapest of disks is likely to hold its data for
more than a decade, provided it is well cared for.
DVD formats, the battle continues:
To understand the variety of
options available in the area of DVD authoring, it's necessary to understand how
the physical media, the DVDs themselves, work.
DVD-ROM or "Digital Versatile Disk - Read Only Memory" media is
currently available in four forms. DVD-5, DVD-9, DVD-10 and DVD-18. It can be
single sided (DVD-5 and -9) or double sided (DVD-10 and -18), and each side
contains a single data layer (DVD-5 and -10) or two data layers (DVD-9 and -18).
DVD-ROMs are the equivalent of 'stamped' CDs and
are mass-produced via injection molding techniques as detailed above. They are
DVD-R is the
original format for
writeable DVD disks, as put forward by the DVD Forum, an assembly of interested companies
founded by Pioneer, Panasonic, Sony and Time-Warner among others. DVD-R disks use much the
same method as CD-R disks to store information. A dye is inserted between the
layers of polycarbonate which can be selectively darkened by the 'write' laser of the DVD-R
drive, so as not to reflect the 'read' laser.
Unlike DVD-ROMs, DVD-R disks
can have only a single data layer on each side of the disk, making for
capacities of 4.7GB single sided and 9.4GB double sided. DVD-R disks can be played back on most commercial
DVD players and drives. They can be written using one of two methods; the 'disk
at once' method burns all required data onto the disk in one continuous write
process, then finalizes the disk so that no more writing is possible. This disk
will then be readable in most DVD players and drives.
Incremental writing can also be done, in which
individual files are added to the disk until it is full, or the author decides
to finalize (or close) the disk. While this is more flexible, it has the
disadvantage that only other drives capable of writing DVD-R disks will be able
to read the media before it has been finalized. The Apple 'Superdrive' is a
DVD-R drive. Since the recording process is similar, most, if not all DVD-R
drives can also write to CD-R media and usually CD-RW also.