Kopetz, H., and Ochsenreiter, W. Clock Synchronization in Distributed Real-Time Systems. IEEE Transactions on Computers, C-36(8), p. 933--939, August 1987.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....hybrid synchronization. Our algorithm realizes a software synchronization but uses the principles of the hardware synchronization (PLL) It does a continuous internal synchronization of each nodes clock to the global time, which is provided by a master. An external synchronization as described in [7] should be done in future work, i.e. by deploying the NTP Protocol. In the following a detailed explanation on the implementation of our synchronization strategy is given. In terms of electrical engineering, the corresponding representations for offset and drift rate are frequency and phase. The ....

....is used, which is the most granular timer within a PC. The error of this counter caused by the quartz oscillators drift rate can be neglected for measuring these small time periods, but the main problems of every software based synchronization are the errors caused by reading the internal clock [7]. In our case the reading of the Time Stamp Counter lasts much longer than one tick of this counter, consequently that its usable precision is reduced. To meet in this problem and for fault tolerance the measured time delays are averaged over time. The maximum and minimum value within the ....

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H. Kopetz and Ochsenreiter. Clock synchronization in distributed real-time systems. IEEE Trans. on Computer, Vol. 36(No. 8):pp. 933--940, August 1987.

....despite faulty processors that can exhibit arbitrary behavior. The paradigm allows us to identify the different imple mentation choices made by each protocol in solving three subproblems it defines. This permits the e.g. Babaoglu Dnunmond 87] Cristian et al. 86] Halpern eta . 84] Kopetz Ochsenreiter 87] Lamport Melliar Smith 84] Lampoft Melliar Smith 85] Lundelius Lynch 84] Mahaney Schneider 85] and [Srikanth Toueg 85] 1. various Byzantine clock synchronization protocols 2 to be compared and the contributions of each to be isolated. Previously, clock synchronization ....

.... 12 convergence clock synchronization algorithm. CFF A was proposed in [Mahaney Schneider 85] CF4t and CFAvg are given in [Dolev et al. 83] CFAvg is the basis for the clock synchronization pro tocol of [Lundelius Lynch 84] and the (AMI S65C60) VLSI clock synchronization chip described by [Kopetz Ochsenreiter 87] Characterizing convergence functions in terms of precision and accuracy was first done by [Mahaney Schneider 85] most of the precision and accuracy functions given in Figure 4.1 were first reported there. 5. Using Agreement for Convergence An agreement protocol allows correct processors in ....

Kopetz, H. and W. Ochsenreiter. Clock synchronization in distributed real time systems. IEEE Transactions on Computers C-$6, 8 (August 1987), 933-940.

....because all system entities depend on the same real time clock [62, s3.1;p51] But, because of the observability problem (See Section 4.1. 2) distributed systems can only make weak assumptions about the ordering of events provided that they do not use an algorithm for global clock synchronization [17]. Ordering of events can be either partial, or total [62, s2.1;p30] Where partial order describes the local sequence of events (in our context locally is on a specific node) and total order describes the global order of events. Thus, unsynchronized systems cannot determine the exact total order ....

....of both the node and of the shared object are set to the same value as the time stamp. Another classic paper that directs the problem of synchronization in distributed environments is Clock Synchronization in Distributed Real Time Systems which was written in 1987 by Kopetz and Ochsenreiter [17]. The paper presents an algorithm for global clock synchronization. 4.3 Global State One big problem that one has to face when implementing a strategy that uses monitoring of a system is that the initial state of the system must be known in order to understand the context of the events recorded ....

Hermann Kopetz and Wilhelm Ochsenreiter. Clock Synchronization in Distributed Real-Time Systems. Transactions on Computers, 36(8):933 -- 940, August 1987.

....to application messages. This is due to the way in which membership is integrated into the communication system, built on a broadcast bus that is accessed using a time division multiple access (TDMA) strategy based on common global time (guaranteed by an approximate synchronization algorithm [Kopetz Ochsenreiter 1987]) In such an architecture, access to the physical medium is divided into dedicated time slots that are allocated a priori to processes in a round robin fashion. The protocol handles process crashes and omissions under the assumption (justified by experimental results [Reisinger 1989] that at ....

H. Kopetz and W. Ochsenreiter, "Clock Synchronization in Distributed Real-Time Systems", IEEE Transactions on Computers, 36 (8), pp.933-40, August 1987.

....most hardware solutions are designed 12 to work in LAN type environments. A notable exception is the CesiumSpray system that uses GPS receivers to synchronize machines, even across WANs [14] Systems also exist that use both hardware and software to synchronize globally timed measurements [15]. Using some hardware can help to reduce the intrusion and improve accuracy of some software algorithms. Many software algorithms are limited by the variance in message transmission times. Using specialized hardware can help in limiting this variance. Many pure software algorithms exist for the ....

H. Kopetz and W. Ochsenreiter, "Clock synchronization in distributed real-time systems," IEEE Transactions on Computers, vol. C-36, pp. 933-940, August 1987.

....of UTC for the University Time Service. Allowing clients to connect directory to Stratum 1 Time Servers is not only a waste of bandwidth, it could also tax the Stratum 1 servers. This may cause unwanted latency and other inaccuracies. Distributed time systems has also been extensively studied[4][5] 6] That is why this next major group, the Stratum 2 Time servers, are necessary. In the particular case of the Ateneo de Manila University. The campus network is configured in such a way that each major group of network users would have their tra#c access certain network gateways. These ....

Kopetz, H., and W. Ochsenreiter. Clock synchronization in distributed real-time systems. IEEE Trans. Computers C-36, 8 (August 1987), 933-939.

....derived from logical clocks based on Lamport s happened before relationship [12] may not be sufficient for this purpose. Messages will have to carry the timestamps obtained from the physical clocks at individual participants. All the physical clocks will have to be synchronized for this purpose [11, 18]. Allowances will have to be made for the fact that it is not possible to perfectly synchronize all clocks in the system. As the order of delivery of messages is influenced by their timestamps, there may be incentives for participants to forge the timestamps of messages they generate. Sometimes, ....

H. Kopetz and W. Ochsenreiter. Clock Synchronization in Distributed Real-Time Systems. IEEE Transactions on Computers, 8:933--940, 1987.

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H. Kopetz and W. Ochsenreiter. Clock Synchronization in Distributed Real-Time Systems. IEEE Transactions on Computers, 36(8):933--940 Aug. 1987.

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H. Kopetz and W. Ochsenreiter. Clock Synchronization in Distributed Real-Time Systems. IEEE Transactions on Computers, 36(8):933--940, Aug. 1987.

No context found.

H. Kopetz and W. Ochsenreiter. Clock Synchronization in Distributed Real-Time Systems. IEEE Transactions on Computers, C-36(8):933--940, 1987.

.... of temporal accuracy of real time information was introduced by Kopetz and Kim [23] 24] The TTP C protocol, which includes a clock synchronization service and a membership service, was first published in 1993 [25] A prototype version of the TTA, including a new clock synchronization chip [26] was built in the context of the European PDCS project. This new prototype implementation has been subject to extensive fault injection experiments [27] 28] From these ex c # 2002 IEEE. To appear in Proceedings of the IEEE Special Issue on Modeling and Design of Embedded Software , Oct. ....

H. Kopetz and W. Ochsenreiter. Clock Synchronization in Distributed Real-Time Systems. IEEE Transactions on Computers, C-36(8):933--940, 1987.

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Kopetz, H., and Ochsenreiter, W. Clock Synchronization in Distributed Real-Time Systems. IEEE Transactions on Computers, C-36(8), p. 933--939, August 1987.

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Kopetz, H. and Ochsenreiter, W. (1987). Clock synchronization in distributed real-time systems. IEEE Transactions on Computers, C-36(8):933--939.

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Kopetz, H., and W. Ochsenreiter. Clock synchronization in distributed real-time systems. IEEE Trans. Computers C-36, 8 (August 1987), 933-939.

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H. Kopetz and W. Ochsenreiter. Clock Synchronization in Distributed RealTime Systems. IEEE Transactions on Computers, 36(8):933--940, Aug. 1987.

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H. Kopetz and W. Ochsenreiter, Clock Synchronization in Distributed Real-Time Systems, IEEE Transactions on Computers. Vol. 36, Nr. 8, pp. 933-940, (1987).

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H. Kopetz, W. Ochsenreiter, "Clock Synchronization in Distributed Real-Time Systems", IEEE Transactions on Computers. Vol. 36, Nr. 8, Aug. 1987, pp. 933-940.

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H. Kopetz and W. Ochsenreiter, "Clock synchronization in distributed real-time systems," IEEE Transactions on Computers, (8):933--940, 1987.

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H. Kopetz, W. Ochsenreiter, "Clock Synchronization in Distributed Real-Time Systems", IEEE Transactions on Computers. Vol. 36, Issue. 8, Aug. 1987, pp. 933-940.

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H. Kopetz and W. Ochsenreiter. Clock synchronization in distributed real time systems. IEEE Transactions on Computers, 36(8), Aug. 1987.

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Kopetz, H., and W. Ochsenreiter. Clock synchronization in distributed real-time systems. IEEE Trans. Computers C-36, 8 (August 1987), 933-939.

No context found.

H. Kopetz and W. Ochsenreiter. Clock Synchronization in Distributed Real-Time Systems. IEEE Trans. Computers, 36(8):933--940, 1987. 9

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Hermann Kopetz and Wilhelm Ochsenreiter. Clock synchronization in distributed real-time systems. IEEE Transactions on Computers, C-36(8):933--939, 1987.

No context found.

H. Kopetz, W. Ochsenreiter, Clock Synchronization in Distributed RealTime Systems, IEEE Transactions on Computers, 1987, pp. 833--839.

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H. Kopetz and W. Ochsenreiter. Clock synchronization in distributed real-time sys- tems. IEEE Trans. Comm.1'36(8):933 9391'Aug. 1987.

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