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

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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

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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