Hardware Reference
In-Depth Information
ProtectDisc
The newest DVD copy protection system is called ProtectDisc. Its DVD-Video version
changes the standard structure of the disc to prevent copying. Unfortunately, a DVD
movie created using ProtectDisc cannot be viewed with PC-based player programs such
as WMP or WinDVD.
Cinavia
Ciniavia (
http://www.cinavia.com/languages/english/index.html
)
is the company respons-
ible for copy-protection for BD movies. If you attempt to create a copy of a BD disc,
Cinavia displays messages such as “Copying Stopped. The content being copied is pro-
tected by Cinavia and is not authorized for copying from this device.” Similar messages
are displayed when attempting to play back an unauthorized copy. Cinavia can also mute
audio from unauthorized copies.
Is Copy Protection “Unbreakable?”
Despitetheclaimsof“unbreakable”copyprotection,ProtectDisc'smethod,liketheothers
discussed here, was quickly overcome. Similarly, enterprising users have figured out how
to bypass Cinavia's copy protection methods (which apply only to BD set-top boxes, not
to BD drives in PCs). As with other copy-protection schemes, legitimate users who don't
try to “beat the system” often wind up being victimized—in the case of ProtectDisk, by
being unable to use a PC to watch the movie.
Optical Drive Performance Specifications
Many factors in a drive can affect performance, and several specifications are involved.
Typical performance figures published by manufacturers are the data transfer rate, the ac-
cess time, the internal cache or buffers (if any), and the interface the drive uses. This sec-
tion examines these specifications.
CD Data Transfer Rate
ThedatatransferrateforaCDdrivetellsyouhowquicklythedrivecanreadfromthedisc
and transfer to the host computer. Normally, transfer rates indicate the drive's capability
for reading large, sequential streams of data.
Transferspeedismeasuredtwoways.Theonemostcommonlyquotedwithopticaldrives
is the “x” speed, which is defined as a multiple of the particular standard base rate. For
example, CD drives transfer at 153.6KBps according to the original standard. Drives
that transfer twice that are 2x, 40 times that are 40x, and so on. DVD drives transfer at
1,385KBps at the base rate, whereas drives that are 20 times faster than that are listed as
20x. Note that because almost all faster drives feature CAV, the “x” speed usually indic-
