PPT-Real Time and Clocks

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. Topics. Logical clocks. Totally-Ordered 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. 558-565.. 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.. st. of January.. It’s Friday.. History of . Clock Making. What we already know about the time:. What are the two . types. of clocks?. What . parts. of clocks do you know?. Can you tell the time?. 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. Susmitha. . kota. . 21-sep-2015. AGENDA. Introduction. Synchronization. Physical Clocks. Global Positioning System. Algorithms. Future Work. References. Introduction: Real . Time System. 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. www.cse.buffalo.edu/~bina/cse486/.../TimeGlobalStatesApr20.ppt. Contents. Introduction. Clocks. , events and process states. Synchronizing . physical clocks. Logical . time & logical . clocks. Contents. . kota. . 21-sep-2015. AGENDA. Introduction. Synchronization. Physical Clocks. Global Positioning System. Algorithms. Future Work. References. Introduction: Real . Time System. 1. . A . deepika. . gopala. . AGENDA. Introduction. Clock Synchronization. Physical Clocks. Global Positioning System. Algorithms. References. Introduction: Synchronization. Communication is important, but how processes synchronize and cooperate with each other is also important.. Canada. Conseil national de recherches. Canada . Activities in Frequency and Time at the. National Research Council of Canada. Research Officers and Research Council Officers:. John Bernard, Group Leader . Canada. Conseil national de recherches. Canada . Activities in Frequency and Time at the. National Research Council of Canada. Research Officers and Research Council Officers:. John Bernard, Group Leader . Time and Clock Time and Clock Primary standard of time = rotation of earth De facto primary standard = atomic clock (1 atomic second = 9,192,631,770 orbital transitions of Cesium 133 atom. Time and Clock Time and Clock Primary standard of time = rotation of earth De facto primary standard = atomic clock (1 atomic second = 9,192,631,770 orbital transitions of Cesium 133 atom. 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.