PPT-Logical Clocks

Topics Logical clocks TotallyOrdered Multicasting Readings L Lamport Time Clocks and the Ordering of Events in Distributed Systems Communications of the ACM Vol 21 No 7 July 1978 pp 558565. The theory of distributed systems shunned the notion of time and intro duced causality tracking as a clean abstraction to rea son about concurrency The practical systems employed physical time NTP information but in a best effort man ner due to the Sarangi Department of Computer Science Indian Institute of Technology New Delhi India Smruti R Sarangi Pastry 125 brPage 2br Synchronous Systems Asynchronous Systems Outline Synchronous Systems Physical Clocks Quartz Clocks Atomic Clocks GPS Network Spring 2009. L. -9 . Logical Time. 1. Announcements. Project 1 update – Thursday. Due 2/26. HW 1 – due Thursday. 2. Last Lecture . –. Clock Sync Important Lessons. Clocks on different systems will always behave differently. Lecture 1. Main Characteristics of Distributed Systems. Independent processors, sites, processes. Message passing. No shared memory. No shared clock. Independent failure modes. CS 271. 2. Distributed System Models. Topics. Logical clocks. Totally-Ordered Multicasting. Vector timestamps. Readings. Van Steen and Tanenbaum: 5.2. Coulouris: 10.4. L. Lamport, “Time, Clocks and the Ordering of Events in Distributed Systems,” . Made by : Enkhdulguun Batsaikhan. Pd:1. Lyrics. Lights go out & it cant be safe. Tides that I tried to swim against. You've put me down upon my knees. Oh I beg, I beg and plead (singing). Come out of things unsaid, Shoot an apple of my head (and a). Generated Clocks. The HCC generates two clocks from the . ePLL. 160 MHz clocks and the chip 40 MHz clock, used as a reference:. An 80 MHz clock using a divide by 2 circuit that contains no loops and so is self clearing.. CS 3220. Fall 2014. Hadi Esmaeilzadeh. hadi@cc.gatech.edu. . Georgia Institute of Technology. Some slides adopted from Prof. . Milos . Prvulovic. Asynchronous vs. . Synchronious. Glitches and delays are . Time keeps on slipping, slipping…. Logistics. Last week’s slides online. Sign up on Piazza now. No really, do it now. Papers are loaded in . HotCRP. Sign up for account at . http://cs7780.ccs.neu.edu. EE324 Lecture 11. Assignment . Start early!. People who are doing well vs. Not doing well. . Last . Time–. RPC. Why remote procedure calls?. Simple way to pass control and data. Elegant transparent way to distribute application. Ken Birman. Cornell University. . CS5410 . Fall 2008. . Real time and clocks. Lamport showed that if we care about event ordering, the best option is to use logical clocks. But suppose we care about real time?. www.cse.buffalo.edu/~bina/cse486/.../TimeGlobalStatesApr20.ppt. Contents. Introduction. Clocks. , events and process states. Synchronizing . physical clocks. Logical . time & logical . clocks. Contents. October 11, 2018. A.F. Cooper. Context and Motivation. How can we synchronize an asynchronous distributed system?. How do we make global state consistent? . Snapshots / checkpoints. Example: Buying a ticket on Ticketmaster. Hadi Esmaeilzadeh. hadi@cc.gatech.edu. . Georgia Institute of Technology. Some slides adopted from Prof. . Milos . Prvulovic. Asynchronous vs. . Synchronious. Glitches and delays are . very. hard to deal with.