Pub Date : 1995-10-25DOI: 10.1109/RTCSA.1995.528748
J. Ng
The Fibre Distributed Data Interface (FDDI) has become a standard for the new generation real-time systems. The correctness of such systems not only depends on the result of the computation and the error-free delivery of the message, it also depends on the time the result is generated and delivered. Messages missing their deadlines are usually of little use to the system. A miss in deadline may result from a degrade in performance to a disaster. The time-token protocol in the FDDl network allocates portions of network bandwidth to the stations (nodes) in the network for transmission. However, there are no standard rules on how to divide the bandwidth among the stations. This paper studies the "normalized proportional allocation scheme" proposed by Wei Zhao and looks into the effect of different packet size towards network utilization and in meeting real-time requirements.
{"title":"The effect of different packet size in a time-token protocol network that supports real-time applications","authors":"J. Ng","doi":"10.1109/RTCSA.1995.528748","DOIUrl":"https://doi.org/10.1109/RTCSA.1995.528748","url":null,"abstract":"The Fibre Distributed Data Interface (FDDI) has become a standard for the new generation real-time systems. The correctness of such systems not only depends on the result of the computation and the error-free delivery of the message, it also depends on the time the result is generated and delivered. Messages missing their deadlines are usually of little use to the system. A miss in deadline may result from a degrade in performance to a disaster. The time-token protocol in the FDDl network allocates portions of network bandwidth to the stations (nodes) in the network for transmission. However, there are no standard rules on how to divide the bandwidth among the stations. This paper studies the \"normalized proportional allocation scheme\" proposed by Wei Zhao and looks into the effect of different packet size towards network utilization and in meeting real-time requirements.","PeriodicalId":111365,"journal":{"name":"Proceedings Second International Workshop on Real-Time Computing Systems and Applications","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132225462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-10-25DOI: 10.1109/RTCSA.1995.528779
Hea-Sook Park, S. Moon, H. Yeo, K. Song
A high performance IPC (Inter-Processor Communication) controller for the multiprocessors of an ATM switching system is proposed in this paper. This IPC controller accommodates the ATM cell assembly and reassembly functions and allows high-speed interprocessor data transfer via ATM switch. The IPC controller structure consists of the segmentation part and the reassembly part for processing AAL type 5. The IPC protocol is implemented sliding window method. The real message ratio and the LPC controller performance is computed according to user packet size. The real message ratio is increased as the user packet size increases because of header overhead. And the maximum real message ratio is about 0.8 in maximum user packet size 496 bytes. The throughput is optimal at packet size 80.
{"title":"An application of real-time IPC controller based ATM cell","authors":"Hea-Sook Park, S. Moon, H. Yeo, K. Song","doi":"10.1109/RTCSA.1995.528779","DOIUrl":"https://doi.org/10.1109/RTCSA.1995.528779","url":null,"abstract":"A high performance IPC (Inter-Processor Communication) controller for the multiprocessors of an ATM switching system is proposed in this paper. This IPC controller accommodates the ATM cell assembly and reassembly functions and allows high-speed interprocessor data transfer via ATM switch. The IPC controller structure consists of the segmentation part and the reassembly part for processing AAL type 5. The IPC protocol is implemented sliding window method. The real message ratio and the LPC controller performance is computed according to user packet size. The real message ratio is increased as the user packet size increases because of header overhead. And the maximum real message ratio is about 0.8 in maximum user packet size 496 bytes. The throughput is optimal at packet size 80.","PeriodicalId":111365,"journal":{"name":"Proceedings Second International Workshop on Real-Time Computing Systems and Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126292606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-10-25DOI: 10.1109/RTCSA.1995.528750
Sang Hyuk Son
The design and implementation of real-time database systems presents many new and challenging problems. Compared with traditional databases, real-time database systems have a distinct feature: they must maintain temporally coherent data while satisfy timing constraints associated with transactions. In addition, a real-time database system must adapt to changes in the operating environment and guarantee the completion of critical transactions. In this paper we address the issues associated with temporal nature of transactions and data, and research areas for advanced real-time database systems.
{"title":"Real-time database systems: present and future","authors":"Sang Hyuk Son","doi":"10.1109/RTCSA.1995.528750","DOIUrl":"https://doi.org/10.1109/RTCSA.1995.528750","url":null,"abstract":"The design and implementation of real-time database systems presents many new and challenging problems. Compared with traditional databases, real-time database systems have a distinct feature: they must maintain temporally coherent data while satisfy timing constraints associated with transactions. In addition, a real-time database system must adapt to changes in the operating environment and guarantee the completion of critical transactions. In this paper we address the issues associated with temporal nature of transactions and data, and research areas for advanced real-time database systems.","PeriodicalId":111365,"journal":{"name":"Proceedings Second International Workshop on Real-Time Computing Systems and Applications","volume":"362 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123129895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-10-25DOI: 10.1109/RTCSA.1995.528766
H. Takada, K. Sakamura
When a real-time system is realized on a shared-memory multiprocessor, the worst-case performance of interprocessor synchronizations is one of the most important issues. In this paper, scalability of the maximum execution times of critical sections guarded by nested spin locks is discussed. With the simplest method, the maximum execution times become O(n/sup m/), where n is the number of contending processors and m is the maximum nesting level of locks. In this paper, we propose an algorithm with which this order can be reduced to O(n/spl middot/e/sup m/) and demonstrate its effectiveness when m=2 through performance measurements.
{"title":"Real-time scalability of nested spin locks","authors":"H. Takada, K. Sakamura","doi":"10.1109/RTCSA.1995.528766","DOIUrl":"https://doi.org/10.1109/RTCSA.1995.528766","url":null,"abstract":"When a real-time system is realized on a shared-memory multiprocessor, the worst-case performance of interprocessor synchronizations is one of the most important issues. In this paper, scalability of the maximum execution times of critical sections guarded by nested spin locks is discussed. With the simplest method, the maximum execution times become O(n/sup m/), where n is the number of contending processors and m is the maximum nesting level of locks. In this paper, we propose an algorithm with which this order can be reduced to O(n/spl middot/e/sup m/) and demonstrate its effectiveness when m=2 through performance measurements.","PeriodicalId":111365,"journal":{"name":"Proceedings Second International Workshop on Real-Time Computing Systems and Applications","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134194540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-10-25DOI: 10.1109/RTCSA.1995.528778
I. Mizunuma, S. Horiike, Morikazu Takegaki
We propose a method for a schedulability check in ATM networks which provide fixed prioritized virtual connections. Our method does not need any run-time scheduling other than fixed priority scheduling at each output link of all switch nodes and traffic shaping at each output link of cell terminal nodes in a network. Rate monotonic analysis assumes a critical instance in which all tasks arrive at the same time. We, however, can obtain information on the times when messages arrive at switch nodes in a network. Using such information, our method can check the schedulability of a set of channels more exactly than the method assuming a critical instance.
{"title":"Real-time communication in plant-monitoring/controlling systems with ATM networks","authors":"I. Mizunuma, S. Horiike, Morikazu Takegaki","doi":"10.1109/RTCSA.1995.528778","DOIUrl":"https://doi.org/10.1109/RTCSA.1995.528778","url":null,"abstract":"We propose a method for a schedulability check in ATM networks which provide fixed prioritized virtual connections. Our method does not need any run-time scheduling other than fixed priority scheduling at each output link of all switch nodes and traffic shaping at each output link of cell terminal nodes in a network. Rate monotonic analysis assumes a critical instance in which all tasks arrive at the same time. We, however, can obtain information on the times when messages arrive at switch nodes in a network. Using such information, our method can check the schedulability of a set of channels more exactly than the method assuming a critical instance.","PeriodicalId":111365,"journal":{"name":"Proceedings Second International Workshop on Real-Time Computing Systems and Applications","volume":"156 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116456939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-10-25DOI: 10.1109/RTCSA.1995.528768
C. Juiz, R. Puigjaner
Design of real-time systems needs to take into account their performance behaviour before their implementation. This goal can be attained by means of queueing network modelling. To process this kind of models normally simulation is used with its inherent costs of debugging and running times. This paper presents the analysis and comparison of several kinds of performance models of a basic software element used in the construction of real-time systems: the producer-consumer. These models go from the simple FIFO queue to the simulation of the complete element passing through some decomposition-aggregation approximate model. This model can be considered as an element of a library and the model of a real-time system can be built by putting together the models of the real-time components.
{"title":"Improved performance model of a real-time software element: the producer-consumer","authors":"C. Juiz, R. Puigjaner","doi":"10.1109/RTCSA.1995.528768","DOIUrl":"https://doi.org/10.1109/RTCSA.1995.528768","url":null,"abstract":"Design of real-time systems needs to take into account their performance behaviour before their implementation. This goal can be attained by means of queueing network modelling. To process this kind of models normally simulation is used with its inherent costs of debugging and running times. This paper presents the analysis and comparison of several kinds of performance models of a basic software element used in the construction of real-time systems: the producer-consumer. These models go from the simple FIFO queue to the simulation of the complete element passing through some decomposition-aggregation approximate model. This model can be considered as an element of a library and the model of a real-time system can be built by putting together the models of the real-time components.","PeriodicalId":111365,"journal":{"name":"Proceedings Second International Workshop on Real-Time Computing Systems and Applications","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123685150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-10-25DOI: 10.1109/RTCSA.1995.528771
S. Yamane
A real-time system consists of many concurrent processes and behaves on strict timing conditions. It is important to verify the timing conditions of a real-time system. In this paper, we propose extended TCTL (Timed CTL) and effective real-time model checking as follows. (1) The timing description of extended TCTL consists of both freeze quantification and bounded temporal operator. For this extension, extended TCTL admits timing constraints between distant contexts. (2) Real time model checking consists of both labelling algorithm and geometric region method. For this method we can avoid the state explosion problem. We have develop the verification system, and show our method to be effective.
{"title":"Verification system for real-time specification based on extended real-time logic","authors":"S. Yamane","doi":"10.1109/RTCSA.1995.528771","DOIUrl":"https://doi.org/10.1109/RTCSA.1995.528771","url":null,"abstract":"A real-time system consists of many concurrent processes and behaves on strict timing conditions. It is important to verify the timing conditions of a real-time system. In this paper, we propose extended TCTL (Timed CTL) and effective real-time model checking as follows. (1) The timing description of extended TCTL consists of both freeze quantification and bounded temporal operator. For this extension, extended TCTL admits timing constraints between distant contexts. (2) Real time model checking consists of both labelling algorithm and geometric region method. For this method we can avoid the state explosion problem. We have develop the verification system, and show our method to be effective.","PeriodicalId":111365,"journal":{"name":"Proceedings Second International Workshop on Real-Time Computing Systems and Applications","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124113461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1995-10-25DOI: 10.1109/RTCSA.1995.528755
K. Kim, L. Bacellar, Yuseok Kim, C. Subbaraman, Hankil Yoon, Jung-Guk Kim, K. Rim
An essential building-block for construction of future real-time computer systems (RTCS's) is a timeliness-guaranteed operating system. The first co-author recently formulated a model of an operating system kernel which can support both real-time processes and new-style real-time objects with guaranteed timely services. The model has been named the DREAM kernel. The key emphasis in formulating the DREAM kernel was in realization of guaranteed timely service capabilities with minimal loss of hardware utilization. This paper presents a summary of the main structuring principles that were exploited to realize guaranteed timely service capabilities together with modularity and expandability in the DREAM kernel. A prototype implementation of the DREAM kernel, v.D2, has been produced by the authors to run on a network of PC's connected by an Ethernet. Several implementation techniques that were adopted during the course of this prototype implementation and may be applicable to other real-time kernel development environments, are briefly discussed in this paper. The prototype kernel (v.D2) has been used to run a real-time object structured non-trivial defense C3 application together with a real-time simulator of the application environment.
{"title":"A timeliness-guaranteed kernel model-DREAM kernel-and implementation techniques","authors":"K. Kim, L. Bacellar, Yuseok Kim, C. Subbaraman, Hankil Yoon, Jung-Guk Kim, K. Rim","doi":"10.1109/RTCSA.1995.528755","DOIUrl":"https://doi.org/10.1109/RTCSA.1995.528755","url":null,"abstract":"An essential building-block for construction of future real-time computer systems (RTCS's) is a timeliness-guaranteed operating system. The first co-author recently formulated a model of an operating system kernel which can support both real-time processes and new-style real-time objects with guaranteed timely services. The model has been named the DREAM kernel. The key emphasis in formulating the DREAM kernel was in realization of guaranteed timely service capabilities with minimal loss of hardware utilization. This paper presents a summary of the main structuring principles that were exploited to realize guaranteed timely service capabilities together with modularity and expandability in the DREAM kernel. A prototype implementation of the DREAM kernel, v.D2, has been produced by the authors to run on a network of PC's connected by an Ethernet. Several implementation techniques that were adopted during the course of this prototype implementation and may be applicable to other real-time kernel development environments, are briefly discussed in this paper. The prototype kernel (v.D2) has been used to run a real-time object structured non-trivial defense C3 application together with a real-time simulator of the application environment.","PeriodicalId":111365,"journal":{"name":"Proceedings Second International Workshop on Real-Time Computing Systems and Applications","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127003268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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