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?  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  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   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   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

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