Information Technology Reference
In-Depth Information
exchange of data in three ways. First, they give each user access to data stored in many
other computers. Second, they support simultaneous file transfers among arbitrary pairs
of computers. Third, they allow users to identify those systems that will be able to deliver
the desired data more rapidly, perhaps because they have a faster Internet connection or
are fewer routing hops away.
Cyberlockers
(also called
file-hosting services
or
cloud storage services
)are
Internet-based file-sharing services that allow users to upload password-protected files.
Users can give other people access to the files they have uploaded by sharing passwords.
People who wish to collaborate on a project often find sharing large files through cy-
berlockers more convenient than sending them back and forth as attachments to email
messages. However, cyberlockers also make it easy for people to share copyrighted ma-
terial, such as songs and movies. In addition, cyberlocker use is much more difficult for
government officials to track than peer-to-peer file sharing.
Napster, which began operation in 1999, was a peer-to-peer network that facilitated
the exchange of music files. In December 1999, the RIAA sued Napster for copyright
infringement, asking for damages of $100,000 each time a Napster user copied a copy-
righted song. In June 2000, the RIAA asked for a preliminary injunction to block Napster
from trading any copyrighted content from major record labels. In February 2001, a fed-
eral appeals court ruled that Napster must stop its users from trading copyrighted mate-
rial. Napster put in place file-filtering software that was 99 percent effective in blocking
the transfer of copyrighted material. In June 2001, a district court judge ruled that unless
Napster could block 100 percent of attempted transfers of copyrighted material, it must
disable file transfers. This court order effectively killed Napster, which went offline in
July 2001 and officially shut down in September 2002 [75, 76, 77]. (The following year
Napster reemerged as an online subscription music service and music store.)
FastTrack is a second-generation peer-to-peer network technology developed by Scan-
dinavians Niklas Zennistrom and Janus Friis. Because of its decentralized design, a Fast-
Track network may be more difficult to shut down than Napster [78, 79].
Figure 4.10 illustrates the differences between the Napster and FastTrack implemen-
tations of peer-to-peer file sharing. Napster relied upon a central computer to maintain
a global index of all files available for sharing. The existence of this central index made
it easy to eliminate the distribution of copyrighted files via Napster.
In contrast, FastTrack distributes the index of available files among a large number
of “supernodes.” Any computer with a high-speed Internet connection running Fast-
Track has the potential to become a supernode. The use of multiple supernodes makes
searching for content slower, but it also makes it much more difficult for legal author-
ities to shut down the file-sharing network. Former peer-to-peer networks Kazaa and
Grokster used the FastTrack technology [80].
