Pub Date : 1998-04-20DOI: 10.1109/ISORC.1998.666792
S. Caughey, M. Little, S. Shrivastava
Traditionally transactions have been single-threaded. In such an environment the thread terminating the transaction is, by definition, the thread which performed the work. Therefore, transaction termination is implicitly synchronised with the completion of the transactional work. With the increased availability of both software and hardware multi-threading, transaction services are being required to allow multiple threads to be active within a transaction. In these systems it is important to guarantee that all threads have completed when a transaction is terminated otherwise some work may not be performed transactionally. In this paper we present a protocol for the enforcement of checked transactional behaviour within an asynchronous environment. We illustrate the use of the protocol within a proposed implementation for a CORBA-compliant Object Transaction Service intended for a soft real-time application which makes extensive use of concurrency and asynchronous message passing.
{"title":"Checked transactions in an asynchronous message passing environment","authors":"S. Caughey, M. Little, S. Shrivastava","doi":"10.1109/ISORC.1998.666792","DOIUrl":"https://doi.org/10.1109/ISORC.1998.666792","url":null,"abstract":"Traditionally transactions have been single-threaded. In such an environment the thread terminating the transaction is, by definition, the thread which performed the work. Therefore, transaction termination is implicitly synchronised with the completion of the transactional work. With the increased availability of both software and hardware multi-threading, transaction services are being required to allow multiple threads to be active within a transaction. In these systems it is important to guarantee that all threads have completed when a transaction is terminated otherwise some work may not be performed transactionally. In this paper we present a protocol for the enforcement of checked transactional behaviour within an asynchronous environment. We illustrate the use of the protocol within a proposed implementation for a CORBA-compliant Object Transaction Service intended for a soft real-time application which makes extensive use of concurrency and asynchronous message passing.","PeriodicalId":186028,"journal":{"name":"Proceedings First International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC '98)","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115473958","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 : 1998-04-20DOI: 10.1109/ISORC.1998.666769
M. Dalmeijer, E. Rietjens, D. Hammer, A. Aerts, M. Soede
This paper describes the design of a novel mobile agent system that supports the flexible and reliable interaction of autonomous components in an object-oriented distributed system. It discusses the object-oriented design of the overall system together with a number of important components in terms of the most important design decisions. A detailed description of the reliability model is given in terms of the failure hypothesis and the related recovery protocols. Special emphasis is given to the generality and efficiency of the implementation and a number of preliminary experiences are described.
{"title":"A reliable mobile agents architecture","authors":"M. Dalmeijer, E. Rietjens, D. Hammer, A. Aerts, M. Soede","doi":"10.1109/ISORC.1998.666769","DOIUrl":"https://doi.org/10.1109/ISORC.1998.666769","url":null,"abstract":"This paper describes the design of a novel mobile agent system that supports the flexible and reliable interaction of autonomous components in an object-oriented distributed system. It discusses the object-oriented design of the overall system together with a number of important components in terms of the most important design decisions. A detailed description of the reliability model is given in terms of the failure hypothesis and the related recovery protocols. Special emphasis is given to the generality and efficiency of the implementation and a number of preliminary experiences are described.","PeriodicalId":186028,"journal":{"name":"Proceedings First International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC '98)","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115985182","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 : 1998-04-20DOI: 10.1109/ISORC.1998.666808
Vikram Gundoju, Toshimi Minoura
We describe a software mechanism that simplifies the implementation of real time distributed object oriented applications. The distributed observable/observer mechanism extends the Observable/Observer concept of Java to a distributed environment encapsulating the communication protocol used by networking. The mechanism supports the distributed model/view controller (M/VC) paradigm, allowing view controllers to be attached to remote models by distributed structural object composition (DSOC). DSOC simplifies the development of distributed real time applications significantly since DSOC objects need only be interconnected to interact properly with each other. We illustrate the distributed observable/observer mechanism with DSOC by examples.
{"title":"Distributed observable/observer: a distributed real-time object-communication mechanism","authors":"Vikram Gundoju, Toshimi Minoura","doi":"10.1109/ISORC.1998.666808","DOIUrl":"https://doi.org/10.1109/ISORC.1998.666808","url":null,"abstract":"We describe a software mechanism that simplifies the implementation of real time distributed object oriented applications. The distributed observable/observer mechanism extends the Observable/Observer concept of Java to a distributed environment encapsulating the communication protocol used by networking. The mechanism supports the distributed model/view controller (M/VC) paradigm, allowing view controllers to be attached to remote models by distributed structural object composition (DSOC). DSOC simplifies the development of distributed real time applications significantly since DSOC objects need only be interconnected to interact properly with each other. We illustrate the distributed observable/observer mechanism with DSOC by examples.","PeriodicalId":186028,"journal":{"name":"Proceedings First International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC '98)","volume":"199 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122752984","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 : 1998-04-20DOI: 10.1109/ISORC.1998.666813
A. Polze, Daniel Plakosh, K. Wallnau
The Object Management Group's (OMG) Common Object Request Broker Architecture (CORBA) is an important and popular technology that supports the development of object based, distributed applications. The benefits promised by CORBA (abstraction, heterogeneity, etc.) are appealing in many application domains, including those that satisfy real time requirements-such as manufacturing. Unfortunately, CORBA was not specified in light of real time requirements, and so the question remains whether existing object request brokers (ORBs) can be used in real time settings, or whether developers of real time systems must await future extensions of CORBA that address real time issues or use non CORBA compliant ORBs. We describe the application of an off the shelf ORB in a real time manufacturing system developed at National institute of Standards and Technology (NIST) and tools which have been developed at the SEI for the analysis of CORBA's impact on the behavior of the system. Based on our experiences, we believe that today's ORBs can be used in real time settings, with certain caveats as outlined in the article. We also outline the concept of "composite objects", an approach for extending the range of non real time ORBs into a greater variety of real time settings.
{"title":"CORBA in real-time settings: a problem from the manufacturing domain","authors":"A. Polze, Daniel Plakosh, K. Wallnau","doi":"10.1109/ISORC.1998.666813","DOIUrl":"https://doi.org/10.1109/ISORC.1998.666813","url":null,"abstract":"The Object Management Group's (OMG) Common Object Request Broker Architecture (CORBA) is an important and popular technology that supports the development of object based, distributed applications. The benefits promised by CORBA (abstraction, heterogeneity, etc.) are appealing in many application domains, including those that satisfy real time requirements-such as manufacturing. Unfortunately, CORBA was not specified in light of real time requirements, and so the question remains whether existing object request brokers (ORBs) can be used in real time settings, or whether developers of real time systems must await future extensions of CORBA that address real time issues or use non CORBA compliant ORBs. We describe the application of an off the shelf ORB in a real time manufacturing system developed at National institute of Standards and Technology (NIST) and tools which have been developed at the SEI for the analysis of CORBA's impact on the behavior of the system. Based on our experiences, we believe that today's ORBs can be used in real time settings, with certain caveats as outlined in the article. We also outline the concept of \"composite objects\", an approach for extending the range of non real time ORBs into a greater variety of real time settings.","PeriodicalId":186028,"journal":{"name":"Proceedings First International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC '98)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114418256","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 : 1998-04-20DOI: 10.1109/ISORC.1998.666809
C. Bernardeschi, L. Simoncini, A. Fantechi
The paper presents an approach for the specification and verification of the correctness of dependable system designs achieved by the application of fault tolerant techniques based on equivalence relations and model checking techniques. The behaviour of the system in absence of faults is formally specified and faults are assumed as random events which interfere with the system by modifying its behaviour. The fault tolerant technique is formalized by a context, which specifies how replicas of the system cooperate to deal with faults. The system design is proved to satisfy the correctness property under a given fault hypothesis, by proving the observational equivalence between the system design specification and the fault free system specification. Additionally, model checking of a temporal logic formula which gives an abstract notion of correct behaviour can be applied to verify the correctness of the design.
{"title":"Validating the design of dependable systems","authors":"C. Bernardeschi, L. Simoncini, A. Fantechi","doi":"10.1109/ISORC.1998.666809","DOIUrl":"https://doi.org/10.1109/ISORC.1998.666809","url":null,"abstract":"The paper presents an approach for the specification and verification of the correctness of dependable system designs achieved by the application of fault tolerant techniques based on equivalence relations and model checking techniques. The behaviour of the system in absence of faults is formally specified and faults are assumed as random events which interfere with the system by modifying its behaviour. The fault tolerant technique is formalized by a context, which specifies how replicas of the system cooperate to deal with faults. The system design is proved to satisfy the correctness property under a given fault hypothesis, by proving the observational equivalence between the system design specification and the fault free system specification. Additionally, model checking of a temporal logic formula which gives an abstract notion of correct behaviour can be applied to verify the correctness of the design.","PeriodicalId":186028,"journal":{"name":"Proceedings First International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC '98)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114465087","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 : 1998-04-20DOI: 10.1109/ISORC.1998.666781
F. Reynolds, R. Clark, F. Travostino
In this paper, we discuss the architecture of MK, its salient features and the evolution of MK from its multi-user, timesharing origins. MK targets a much broader class of applications than typical real-time executives so it must provide more sophisticated functionality than the typical real-time OS (RTOS). In addition to standard features such as pre-emptive scheduling and resource partitioning, MK is designed as a multi-level collection of frameworks that separate mechanisms from policies at each level of abstraction and enable mission specific customization. MK also provides innovative kernel abstractions such as trans-node, migrating threads and "paths", which greatly enhance both the "composibility" of the system and its ability to support a variety of end-to-end Qualities of Services.
{"title":"Evolution of a distributed, real-time, object-based operating system","authors":"F. Reynolds, R. Clark, F. Travostino","doi":"10.1109/ISORC.1998.666781","DOIUrl":"https://doi.org/10.1109/ISORC.1998.666781","url":null,"abstract":"In this paper, we discuss the architecture of MK, its salient features and the evolution of MK from its multi-user, timesharing origins. MK targets a much broader class of applications than typical real-time executives so it must provide more sophisticated functionality than the typical real-time OS (RTOS). In addition to standard features such as pre-emptive scheduling and resource partitioning, MK is designed as a multi-level collection of frameworks that separate mechanisms from policies at each level of abstraction and enable mission specific customization. MK also provides innovative kernel abstractions such as trans-node, migrating threads and \"paths\", which greatly enhance both the \"composibility\" of the system and its ability to support a variety of end-to-end Qualities of Services.","PeriodicalId":186028,"journal":{"name":"Proceedings First International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC '98)","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124599466","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}
As real-time systems become larger and more complex, attempts to apply the object-oriented paradigm to real-time systems are being made. We introduce a real-time object (RTO) model that is suitable for dynamic real-time environments. We also propose a scheduling algorithm and an implementation of a real-time scheduler for the RTO model. We developed the LLF/MP scheduling algorithm that is good for dynamic real-time environments. A real-time scheduler for the RTO model and LLF/MP scheduling algorithm must guarantee the temporal constraints of both the real-time method and the real-time message, and support an infinite real-time queue efficiently, which LLF/MP needs. To solve these problems, we propose a data structure, RT-HashQ (Real-Time-Hash Queue).
{"title":"RT-HashQ for RTO scheduling","authors":"Seung-Min Yang, Sheen Lee, Hyung-Taek Lim, Sung-Heun Oh","doi":"10.1109/ISORC.1998.666776","DOIUrl":"https://doi.org/10.1109/ISORC.1998.666776","url":null,"abstract":"As real-time systems become larger and more complex, attempts to apply the object-oriented paradigm to real-time systems are being made. We introduce a real-time object (RTO) model that is suitable for dynamic real-time environments. We also propose a scheduling algorithm and an implementation of a real-time scheduler for the RTO model. We developed the LLF/MP scheduling algorithm that is good for dynamic real-time environments. A real-time scheduler for the RTO model and LLF/MP scheduling algorithm must guarantee the temporal constraints of both the real-time method and the real-time message, and support an infinite real-time queue efficiently, which LLF/MP needs. To solve these problems, we propose a data structure, RT-HashQ (Real-Time-Hash Queue).","PeriodicalId":186028,"journal":{"name":"Proceedings First International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC '98)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130496208","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 : 1998-04-20DOI: 10.1109/ISORC.1998.666800
M. Hurfin, M. Raynal
This paper investigates the use of asynchronous protocols to design and build middleware whose aim is to provide run-time support for soft real-time applications. A simple and general framework is described. This framework allows to take into account timeliness constraints of upper layer applications, while using an asynchronous protocol at the underlying level. When a timeliness constraint is about to be violated, the application layer is informed and can take appropriate measures. The deadline period can then be extended if the constraint is soft enough; in the other case, a default value can be used as a result. This framework can be seen as a bridge from asynchronous systems to synchronous ones. The proposed approach is illustrated with the consensus problem. This approach is investigated in the ARGO system we are implementing. The target applications of the ARGO middleware are telecommunication applications.
{"title":"Asynchronous protocols to meet real-time constraints: is it really sensible? How to proceed?","authors":"M. Hurfin, M. Raynal","doi":"10.1109/ISORC.1998.666800","DOIUrl":"https://doi.org/10.1109/ISORC.1998.666800","url":null,"abstract":"This paper investigates the use of asynchronous protocols to design and build middleware whose aim is to provide run-time support for soft real-time applications. A simple and general framework is described. This framework allows to take into account timeliness constraints of upper layer applications, while using an asynchronous protocol at the underlying level. When a timeliness constraint is about to be violated, the application layer is informed and can take appropriate measures. The deadline period can then be extended if the constraint is soft enough; in the other case, a default value can be used as a result. This framework can be seen as a bridge from asynchronous systems to synchronous ones. The proposed approach is illustrated with the consensus problem. This approach is investigated in the ARGO system we are implementing. The target applications of the ARGO middleware are telecommunication applications.","PeriodicalId":186028,"journal":{"name":"Proceedings First International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC '98)","volume":"513 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"113995692","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 : 1998-04-20DOI: 10.1109/ISORC.1998.666812
K. Kusunoki, I. Imai, Haruyuki Ohtani, T. Nakakawaji, Michitaka Ohshima, K. Ushijima
Supporting rapid response to changing customer requirements, reduction in both time and cost of manufacturing process, and integration within a heterogeneous wide area networked enterprise are necessary to increase worldwide competitiveness in manufacturing. We propose a CORBA based architecture to realize that manufacturing environment. We have developed an ORB for PLC to realize that architecture. And we have developed two prototypes of a remote monitoring system for factory automation, which are a manufacturing line monitoring system and a remote PLC monitoring system which uses a Web browser, to examine feasibility and effectiveness of the proposed architecture. According to experiments with these prototypes, we show the feasibility and effectiveness of our proposed CORBA based architecture.
{"title":"A CORBA-based remote monitoring system for factory automation","authors":"K. Kusunoki, I. Imai, Haruyuki Ohtani, T. Nakakawaji, Michitaka Ohshima, K. Ushijima","doi":"10.1109/ISORC.1998.666812","DOIUrl":"https://doi.org/10.1109/ISORC.1998.666812","url":null,"abstract":"Supporting rapid response to changing customer requirements, reduction in both time and cost of manufacturing process, and integration within a heterogeneous wide area networked enterprise are necessary to increase worldwide competitiveness in manufacturing. We propose a CORBA based architecture to realize that manufacturing environment. We have developed an ORB for PLC to realize that architecture. And we have developed two prototypes of a remote monitoring system for factory automation, which are a manufacturing line monitoring system and a remote PLC monitoring system which uses a Web browser, to examine feasibility and effectiveness of the proposed architecture. According to experiments with these prototypes, we show the feasibility and effectiveness of our proposed CORBA based architecture.","PeriodicalId":186028,"journal":{"name":"Proceedings First International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC '98)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130431706","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 : 1998-04-20DOI: 10.1109/ISORC.1998.666820
L. Bacellar, B. Upender
Decreasing hardware costs is permitting the increased use of embedded computers to support complex and sophisticated applications in a variety of products. Many of these applications require computing nodes distributed in different physical locations interconnected by communication networks. The object oriented model with its well known properties that facilitate the design of complex software applications is a natural choice for designing distributed embedded system applications. Existing models that support remote method invocation (RMI) in object oriented distributed computer systems are more tailored towards general distributed computer systems rather than embedded systems. Moreover, efficient implementations of these RMI models are rare at this time. We analyze predominant RMI models with respect to essential features for embedded applications such as timeliness and fault handling capability. Based on this analysis, we propose the Distributed Embedded Object Model (DEOM), dependable, distribution-transparent RMI model to support the execution of distributed embedded system applications.
{"title":"A dependable distribution-transparent remote method invocation model for object-oriented distributed embedded computer systems","authors":"L. Bacellar, B. Upender","doi":"10.1109/ISORC.1998.666820","DOIUrl":"https://doi.org/10.1109/ISORC.1998.666820","url":null,"abstract":"Decreasing hardware costs is permitting the increased use of embedded computers to support complex and sophisticated applications in a variety of products. Many of these applications require computing nodes distributed in different physical locations interconnected by communication networks. The object oriented model with its well known properties that facilitate the design of complex software applications is a natural choice for designing distributed embedded system applications. Existing models that support remote method invocation (RMI) in object oriented distributed computer systems are more tailored towards general distributed computer systems rather than embedded systems. Moreover, efficient implementations of these RMI models are rare at this time. We analyze predominant RMI models with respect to essential features for embedded applications such as timeliness and fault handling capability. Based on this analysis, we propose the Distributed Embedded Object Model (DEOM), dependable, distribution-transparent RMI model to support the execution of distributed embedded system applications.","PeriodicalId":186028,"journal":{"name":"Proceedings First International Symposium on Object-Oriented Real-Time Distributed Computing (ISORC '98)","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1998-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117278578","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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