Transcript Chapter 38 - Personal Web Pages

ITIS 1210
Introduction to Web-Based
Information Systems
Chapter 38
How Music Sharing and File Sharing Work
Introduction
 Internet is not just another data delivery
mechanism
 Potential to change society in profound ways
 Other examples?
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Printing press
Tape recorders
Photocopiers
VCR
Introduction
 Music-sharing
 Changed the way people used the Internet
 Threatened traditional music industry
 How?
 Let people share their own music with others
 Make a copy of your CD
 Post your copy where others can access it
 And copy it to their PCs
 Copy files others have posted to your PC
Introduction
Napster
 Music industry’s reaction?
 Lawsuit
 Copyright violation
 First major company sued was Napster
Napster
Napster
 Shaun Fanning
 Student at Northeastern U.
 Beta version given to 30
friends on June 1, 1999
 Within a few days 10,000 to
15,000 people had
downloaded it
 Used central servers
Napster
Napster
 Metallica discovered ”I Disappear” was
circulating before its release
 Filed suit in 2000
 Dr Dre requested his works
be removed
 Filed suit when Napster
declined
Napster
 Music industry sued in December 1999
 Napster lost but appealed
 Only facilitators, not their fault users were using
their service illegally
 Ninth Circuit Court issued injunction in
March 2001
 Napster shut down in July 2001
 Paid $26,000,000 settlement
 Bankruptcy followed in September 2002
Napster
 Roxio acquired assets
 Launched Napster 2.0
 Paved the way for
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iTunes
Grokster
Gnutella
Kazaa
Peer-to-Peer Network
 Does not use a central server
 Individual users communicate separately
 Share software, movies, sound files, etc.
 Business peer-to-peer now popular
 www.groove.net
 Enables workers to create private workspace
to share files, messages, software
 Irony: guerilla movement embraced by
corporate America
Kazaa
 Download Kazaa and install it on your PC
 www.kazaa.com
 Software connects to a Kazaa server
 Your PC receives a list of supernodes
 Localized search sites for the file-sharing network
 Ordinary PCs with
 High-speed Internet connections
 Powerful processors
 Your PC could become a supernode
Kazaa
 Your PC contacts a nearby supernode
 Sends to it information about all the music
files on your computer
 Name of recording
 Your IP address
 Your Kazaa ID
 Supernode stores this information it its
database
Kazaa
 When you search for music you supply
 Name of artist
 Song title
 Kazaa contacts nearest supernode
 Which may contact other supernodes
 Builds a list of matching titles and
computers they’re stored on
Kazaa
 You choose which one you want
 Software downloads it directly from
computer you picked
 Not from supernode
BitTorrent
 Another technology for file sharing
 Not just audio files
 Videos, spreadsheets, etc.
 Entire CDs
 Also enables corporations to efficiently
distribute software to multiple locations
 Latest version of company applications that
need to be distributed to many offices at once
(i.e., a new release)
BitTorrent
 Operates somewhat differently
 Downloads parts of final content
 From multiple sites
 Assembled at destination
 Starts by downloading and installing client
software
 Freely available from www.bittorrent.com
BitTorrent
 Users visits a site specializing in BitTorrent
downloads
 Site downloads a torrent file
 “Pointer” file containing information and
instructions
 Where and how a file can be downloaded
 Included is address of a tracker server
 Also filename, size, checksum of every block
to be downloaded
BitTorrent
 BitTorrent client talks to tracker server that
provides
 Address information of all computers that
have the requested file or portions thereof
 These are seed computers
 Every seed computer with all or part of the file
is called a swarm
 Downloading from seed computers
happens simultaneously
BitTorrent
 Speeds up the overall process significantly
 Once assembled the complete file is used
as normal
 Downloading can happen at the same time
as uploading
 The Client can be working in both directions
to assist other BitTorrent users
BitTorrent
 BitTorrent controls client privileges
 Clients that leave BitTorrent running
 And thus upload to other computers more
 Will be given privileges to download faster
 Than computers that rarely upload