PPT-I/O Systems (3): Clocks and Timers

1 CSE 2431 Introduction to Operating Systems Instructor Adam C Champion PhD Outline Clock Hardware Clock Software Soft Timers 2 Two Types of Clocks Simple clock tied to 110 or 220volt power line causes an interrupt at every voltage cycle 50 or 60 Hz. 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. 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 . by. Dr. Amin Danial Asham. References. Programmable . Controllers-Theory and Implementation, 2nd Edition, L.A. Bryan and E.A. Bryan . Timers. PLC timers . are . internal instructions that provide the . Xen. Bhanu Vattikonda. with . Sambit. Das and . Hovav. . Shacham. 2. Motivation . Project goals. Goals of the paper. Discussion . Future work. Motivation. 3. Recent research efforts have shown that covert channel attacks are possible in the cloud using fine grained timers . Ticker Timers Graph 1. V= s/t. . = 0.23 m / 0.18 s. . = 1.28ms. -1. Ticker timers Graph 2. V= s / t. . = 0.5 / 0.12 . . = 4.17ms. -1. . Gradient = Rise over Run. y. 2-y1 / x2-x1 . In a s/t graph represents ?. 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. Produced by Dave Foord. Terms of use. These timers are free for anyone to use within education or not for profit organisations.. You are entitled to download this presentation and add to your own internal system (e.g. VLE) to distribute to others.. 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 . s and. . Time. r. s. An. . embed. d. ed. . s. y. s. t. em. . h. a. v. e. . t. o. . r. espo. n. d. . t. o. . e. v. e. n. ts. . whe. r. e. . t. i. m. i. ng. . i. s. . a. . k. e. y. c. on. s. 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.