PPT-Peer-to-Peer Systems and Distributed Hash Tables

COS 518 Advanced Computer Systems Lecture 15 Daniel Suo Credit All slides copied wholesale from Kyle Jamieson and Mike Freedman Selected content adapted from B Karp R Morris. Spencer Dawson. Summary. What are rainbow tables?. A time and memory tradeoff in password cracking.. A piecewise approach to one-way hashes. What are the advantages/disadvantages. Best uses. Limitations. Passwords stored in computers are changed from their plain text form to an encrypted value.. These values are called hashes, and there is a unique plain text value for every hash.. A rainbow table is a lookup table offering a time-memory tradeoff used in recovering the plaintext password from a password hash generated by a hash function . Sig Freund. CSC 8320 Fall . 2008. rfreund1@student.gsu.edu. Transparency in Distributed Operating Systems. Evolution of Modern Operating Systems. Centralized operating system. +network access and resource sharing. Distributed Storage. 1. Dennis Kafura – CS5204 – Operating Systems. CS 5204 – Operating Systems. 2. Peer-to-Peer Systems. Definition. : “Peer-to-peer systems can be characterized as distributed systems in which all nodes have identical capabilities and responsibilities, and all communication is symmetric.” –. CIS 606. Spring 2010. Hash tables. Many applications require a dynamic set that supports only the . dictionary . operations . INSERT. , SEARCH, and DELETE. Example: a symbol table in a compiler.. A hash table is effective for implementing a dictionary.. 11/8/2017. Recap: Parallel Query Processing. Three main ways to parallelize. 1. Run multiple queries, each on a different thread. 2. Run operators in different threads (“pipeline”). 3. Partition data, process each partition in a different processor. We have:. Discussed techniques for hashing. Discussed mapping down to a given range . 0, ..., . M. – 1. Now we must deal with collisions. Numerous techniques exist. Containers in general. Specifically linked lists. Hash Tables. . . 0. 1. 2. 3. 4. 451-229-0004. 981-101-0002. 025-612-0001. © 2014 Goodrich, Tamassia, Godlwasser. Presentation for use with the textbook . Data Structures and Algorithms in Java, 6. COS 518: . Advanced Computer Systems. Lecture 16. Michael Freedman. [Credit: Slides Adapted from Kyle Jamieson and Daniel . Suo. ]. Peer-to-Peer Systems. Napster, Gnutella, BitTorrent, challenges. Distributed Hash Tables. Instructor: Lilian de Greef Quarter: Summer 2017 CSE 373: Data Structures and Algorithms Lecture 6: Finishing Amortized Analysis; Dictionaries ADT; Introduction to Hash Tables Today: Finish up Amortized Analysis COS 418: . Distributed Systems. Lecture 7. Kyle Jamieson. [Credit: Selected content adapted from B. Karp, R. Morris]. Peer-to-Peer Systems. Napster, Gnutella, BitTorrent, challenges. Distributed Hash Tables. Distributed Hash Tables. Chord, . Kelips. , Dynamo. Galen Marchetti, Cornell University. 1960s – 1999: Research Origins. ARPANET. every node requests and serves content. No self-organization. USENET. A common approach is to use a . Distributed Hash Table. (DHT). to organize . nodes. Traditional . hash functions convert a key to a hash value, which can be used as an index into a hash table.. Keys are unique. Dr. . Barsha. . Mitra. CSIS . Dept. , BITS Pilani, Hyderabad Campus. Introduction. Course ID: SS ZG526, Title: Distributed Computing. allows for flexibly sharing resources (e.g., files and multimedia documents) stored across network-wide computers.