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746 Chapter <strong>13</strong> Optical Storage<br />
When DVD-RAM was first introduced, the disc had to remain in a caddy because the recordable surface<br />
is delicate. Since then, DVD-RAM drives have been made caddy-less, but especially with doublesided<br />
discs the information is at risk every time you handle the disc. Because of this fragility, as well<br />
as the general incompatibility of DVD-RAM with DVD-ROM, I recommend DVD+RW as the best solution<br />
for recordable DVD. No caddy is required with DVD+RW, and the format is fully two-way compatible<br />
with DVD-Video and DVD-ROM.<br />
Slot<br />
Some drives now use a slot-loading mechanism, identical to that used in most automotive CD players.<br />
This is very convenient, because you just slip the disc into the slot, where the mechanism grabs it and<br />
draws it inside. There are drives that can load several CDs at a time this way, holding them internally<br />
inside the drive and switching discs as access is required.<br />
The primary drawback to this type of mechanism is that if a jam occurs, it can be much more difficult<br />
to repair because you might have to remove the drive to free the disc. Another drawback is that slotloading<br />
drives normally can’t handle the smaller 80mm discs, card-shaped discs, or other modified<br />
disc physical formats or shapes.<br />
Other Drive Features<br />
Although drive specifications are of the utmost importance, you should also consider other factors<br />
and features when evaluating CD-ROM drives. Besides quality of construction, the following criteria<br />
bear scrutiny when making a purchasing decision:<br />
■ Drive sealing<br />
■ Self-cleaning lenses<br />
■ Internal versus external drive<br />
Drive Sealing<br />
Dirt is your CD/DVD drive’s biggest enemy. Dust or dirt, when it collects on the lens portion of the<br />
mechanism, can cause read errors or severe performance loss. Many manufacturers seal off the lens<br />
and internal components from the drive bay in airtight enclosures. Other drives, although not sealed,<br />
have double dust doors—one external and one internal—to keep dust from the inside of the drive. All<br />
these features help prolong the life of your drive.<br />
Some drives are sealed, which means that no air flows through the chamber in which the laser and<br />
lens reside. Always look for sealed drives in harsh industrial or commercial environments. In a standard<br />
office or home environment, it is probably not worth the extra expense.<br />
Self-Cleaning Lenses<br />
If the laser lens gets dirty, so does your data. The drive will spend a great deal of time seeking and<br />
reseeking or will finally give up. Lens-cleaning discs are available, but built-in cleaning mechanisms<br />
are now included on virtually all good-quality drives. This might be a feature you’ll want to consider,<br />
particularly if you work in a less-than-pristine work environment or have trouble keeping your desk<br />
clean, let alone your drive laser lens. You can clean the lens manually, but it is generally a delicate<br />
operation requiring that you partially disassemble the drive. Also, damaging the lens mechanism by<br />
using too much force is pretty easy to do. Because of the risks involved, in most cases I do not recommend<br />
the average person dissasemble and try to manually clean the laser lens.
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