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Transcript of 2013.12.11 102062551 徐晨桓 9762113 李柏穎. Definition Introduction History Example -...
MULTI-USER FILE SHARING SYSTEM
2013.12.11
102062551 徐晨桓 9762113 李柏穎
徐晨桓 李柏穎
OUTLINE
Definition Introduction History Example - Napster Example - Gnutella
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DEFINITION
File system + File sharing + Multi-user
Synchronization in OS (Single user)
multi-user operating system
Network File System (NFS)
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PROTECTION File owner/creator
Types of accessRead 、 Write 、 Execute 、 Append 、 Delete 、 List
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EXCLUSIVE VS. SHAREABLE
An active file is open to one or more run units.
An inactive file is one that is not open to any run unit.
Active files can be open in one of two modes: exclusive or shareable:
Exclusiveopen to one run unit only
Shareableavailable to any number of run units
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NETWORK FILE SHARING (NFS)Peer-to-Peer (P2P) File Sharing most popular, but
controversial
Network computer users locate shared data.
collecting and segmenting large files into smaller pieces.
File Hosting Services
alternative provides a broad selection of popular online material.
These service websites usually host files to enable users to download them.
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HISTORY Files were first exchanged on removable media.
bulletin board systems (1978), Usenet (1979), and FTP servers (1985). Internet Relay Chat (1988) and Hotline (1997) enabled users to communicate remotely through chat and to exchange files.
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HISTORY
In June 1999, Napster was released as an unstructured centralized peer-to-peer system.
Gnutella was the first decentralized file sharing network.no central point of failure
Freenet was released and became the first anonymity network.
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HISTORY
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OUTLINE
Definition Introduction History Example - Napster Example - Gnutella
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Release in 1999
pioneering p2p file sharing Internet service
MP3 file sharing
John Fanning, Shawn Fanning and Sean Parker
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Hybrid P2P
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Redefine the music industry and the way we all think about intellectual property. 1000s of copies of copyrighted songs
Shutdown in 2001
Restart in 2003 as non-free service
Currently become online music store
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Hybrid P2P
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OUTLINE
Definition Introduction History Example - Napster Example - Gnutella
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Gnutelladecentralized P2P File Sharing Network
G
徐晨桓 李柏穎
GNUTELLA
First Decentralized p2p network, pure P2P
Released in 2000, open source
Developed by Justin Frankel & Tom Pepper
Released on web of American Online
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GNUTELLA Ping
Pong
7 Hops
Query
Hit
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•Ultrapeers
•Leaf
GNUTELLA
ask file A
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•Ultrapeers
•Leaf
•QRP
GNUTELLA
ask file A
Query Routing Protocol
Saving 70% traffic
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•Ultrapeers
•Leaf
•QRP
•DR
GNUTELLA
ask file A
Dynamic Routing
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•Ultrapeers
•Leaf
•QRP
•DR
GNUTELLA
ask file A
Dynamic Routing
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•Ultrapeers
•Leaf
•QRP
•DR
• Finding sources
without searching
GNUTELLA
ask file A
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GNUTELLA
•Ultrapeers
•Leaf
•QRP
•DR
• Finding sources without searching
• Swarming and Partial File Sharing
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GNUTELLA
leaf
Ultrapeer
leaf
•Ultrapeers
•Leaf
•QRP
•DR
• Finding sources without searching
• Swarming and Partial File Sharing
•Firewall25/27
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GNUTELLA
Was taken down the next day after releasing This did not stop Gnutella
Open source clones started showing up
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REFERENCE
http://web.cs.wpi.edu/~rek/DCS/D04/FileSystemsInterface.pdf
http://documentation.microfocus.com/help/index.jsp?topic=%2Fcom.microfocus.eclipse.infocenter.enterprisedeveloper.eclipsewin%2FHRLHLHPDF61F.html
http://www.techopedia.com/definition/16256/file-sharing
http://gnufu.net
http://en.wikipedia.org
http://whatis.techtarget.com
http://computer.howstuffworks.com
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THANK YOU FOR LISTENING