D. C. Schmidt and F. Kuhns. An Overview of the Real-Time CORBA Specification. IEEE Computer, 33(6):56--63, 2000.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....interactions. The STI standard also specifies the provision of the three interfaces through a CORBA server. However, currently there is no CORBA architecture for effectively supporting the temporal requirements to establish the RS interface. Current priority based approaches like Real time CORBA [16] require complete knowledge about all other service requests and their corresponding priority values in the whole CORBA network. However, the availability of a global notion of time allows to record the instant of the acquisition of a real time entity s state in each observation. 7 Conclusion We ....

D. C. Schmidt and F. Kuhns. An overview of the real-time CORBA specification. IEEE Computer, 33(6):56--63, 2000. 8

....CORBA priorities. 2.2. Basic Real Time CORBA Features To understand the integration of our CAN protocol into Real Time CORBA, this section explains the necessary features of the Real Time CORBA specification. A more detailed description of the Real Time CORBA specification is given in [16] and [20]. The original CORBA specification supports only implicit bindings, establishing resources on demand. For real time applications with deterministic Quality ofService (QoS) requirements these implicit bindings are inadequate. Real Time CORBA defines explicit binding mechanisms which improve the ....

D. C. Schmidt and F. Kuhns. An Overview of the Real-Time CORBA Specification. IEEE Computer, 33(6):56--63, 2000.

....is part of the CORBA Specification [6] is introduced. The Realtime CORBA standard defines some extensions to CORBA and together with the Minimum CORBA specification [16] it puts some restrictions on the use of CORBA 2.5 Realtime CORBA 17 parts, that conflict with realtime predictability. In [17] Schmidt and Kuhns give a good introduction into the key features of the realtime CORBA specification. Extensions are divided into (1) those for management of processor resources and (2) those for the management of inter ORB communication. For the management of processor resources, RTCORBA ....

....binding) Resource allocation then takes place at the time of invocation, leading to a significantly increased latency and jitter. To ensure a maximum latency, explicit binding can be used. For more information about the extensions of RTCORBA, see the overview of the realtime CORBA specification [17] and the RTCORBA specification itself [15] 2.6. CAN Bus In this section the Controller Area Network (CAN) is introduced. As it plays an important role in this diploma thesis, even some detail is given. Still, a complete introduction would go beyond the scope of this document and is left to ....

Douglas C. Schmidt and Fred Kuhns. An Overview of the Real-time CORBA Specification. Computer, 33(6):56--63, 2000. 17, 18

....are provided and some conclusions are drawn in section 6. 2. Real Time CORBA It is not possible to describe the whole Real Time CORBA specification in this paper, but it explains the most important components. A detailed description of the RealTime CORBA specification is given in [15] and [18]. A standard ORB handles all requests of clients in a unique way. This way of processing is of course not suitable for real time ORBs. Generally, different clients which operate with different priorities send several requests to the server. A multithreaded server possesses a pool of threads that ....

D. C. Schmidt and F. Kuhns. An overview of the real-time corba specification. IEEE Computer, 33(6):56--63, 2000.

....made to enhance these middleware with features to support special purpose applications. For example, the CORBA specification has been enhanced to include multithreading, priority based scheduling, and controlled priority inversion at the ORB level to support real time and embedded applications [74, 68]. Similar efforts have been made to augment Java to support real time features [66, 27] A recently adopted CORBA specification also provides directives for constructing fault tolerant CORBA objects using replication [24] Orthogonal to the above efforts, which accommodate the needs of modern ....

D. Schmidt and F. Kuhns. An Overview of the Real-Time CORBA Specification. IEEE Computer, 33(6):56--63, June 2000.

....specification of the MT method. These specifications are advertised to the designers of potential client objects. A middleware that supports the TMO model and that is based on the standard CORBA API has been implemented on Windows NT. Real Time CORBA The Real Time CORBA (RT CORBA) specification [OMG99b, Sch00] adopts a similar approach. It extends the CORBA standard by interfaces and QoS policies that allow applications to configure and control the various resources: 1. Processor resources: RT CORBA defines thread pools that allow to control the mapping of multiple treads to certain interfaces. It ....

....and real time aspects) already has been implemented in some distributed object oriented systems and distributed transaction systems, e.g. Cah93] However, it is not part of the specification of neither CORBA nor DCOM. The first standard that contained it was the Real Time CORBA specification [OMG99b, Sch00]. It states that an abstract activity is represented in an ORB by concrete entities: a message within a transport protocol, a request held in memory, and a thread scheduled to run on a processor. These three phases are termed in transit , static and active respectively. Real Time CORBA ....

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Schmidt, D. C., Kuhns, F., An Overview of the Real-Time CORBA Specification, IEEE Computer Magazine, Special Issue on Object-oriented Real-time Computing, Vol. 33, No. 6, pp. 5663, 2000.

....the control actions necessary to keep the application QoS between bounds. This framework shares many design concerns with our framework, although it has been targeted to the control of applications. OMG currently develops Real time CORBA facilities in the scope of the CORBA 3. 0 standard [15]. These facilities allow one to manipulate some middleware characteristics that influence the QoS, such as, e.g. the properties of protocols underlying the ORB and the threading and priority polices applied to the handling of requests by server objects. These facilities are defined in terms of ....

D.C. Schmidt, F. Kuhns. An overview of the real-time CORBA specification. To appear in: IEEE Computer special issue on Object-oriented real-time distributed computing, June 2000.

....support for functionality such as load balancing, fault tolerance, real time characteristics and quality of service specifications making CORBA unsuitable for deployment within time critical applications. However due to the adoption of asynchronous messaging [6] and research into real time CORBA [7,8,9,10,21], CORBA now represents a technology mature enough to provide much of the functionality required in DVE development. Typically, most DVE applications and DVE development toolkits use distributed callbacks extensively as a method of event notification [1,13,14,15,16] Distributed callbacks are ....

Douglas C. Schmidt and Fred Kuhns, "An Overview of the Real-time CORBA Specification", IEEE Computer, Special Issue on Object-Oriented Real-time Distributed Computing, edited by Eltefaat Shokri and Philip Sheu, June 2000.

....control system design. In particular, new component based architectures [1] 2] encourage flexible plug and play extensibility and evolution of systems. Distributed object computing allows heterogeneous components to interoperate across diverse platforms and network protocols [1] 3] [4]. Newadvances are being made to enable the dynamic reconfiguration and evolution of systems while they are still running [5] 7] New communication technologies are being developed to allow networked, embedded devices to connect to each other and self organize [8] This article describes a new ....

....computing and reconfiguration technology so that a controls engineer can exploit these technologies without being an expert in computer science or computer engineering. In the bottommost core layer, the OCP leverages from and extends new advances in real time distributed object computing [3] [4], 27] which allow distributed, heterogeneous components to communicate asynchronously in real time. It also supports highly decoupled interaction between the distributed components of the system, which tends to localize architectural or configuration changes so that they can be made quickly and ....

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D. Schmidt and F. Kuhns, "An overview of the real-time CORBA specification, " IEEE Computer, vol. 33, no. 6, pp. 56-63, June 2000.

....focus on adaptive applications and resource management in a distributed system. Unlike these systems, CRM is designed to be portable between OSs that provide di#erent scheduling abstractions, and takes the viewpoint that few desktop applications are capable of automatic adaptation. RT CORBA 1. 0 [13] assumes that systems it runs on provide fixed priority scheduling, and it provides a consistent view of priorities across a distributed heterogeneous system. Recent RT CORBA work [3] is more ambitious with respect to scheduler diversity and has the goal of ensuring semantic correctness of ....

D. C. Schmidt and F. Kuhns. An Overview of the Real-time CORBA Specification. IEEE Computer, 33(6), June 2000.

....heterogeneous components to interoperate across diverse platforms and network protocols in real time. Specifically, we have successfully leveraged from two different distribution substrates. One is being developed by Boeing Phantom Works and Washington University and is based on Real Time CORBA [10]. CORBA, which stands for Common Object Request Broker Architecture, is a standard set by the Object Management Group (OMG) 11] to achieve seamless distributed communication between objects running on different computers and across multiple network protocols. Real time CORBA extends CORBA ....

D. Schmidt and F. Kuhns. An Overview of the Real-Time CORBA Specification, IEEE Computer, vol. 33, no. 6, pp. 56-63, June 2000.

....the control actions necessary to keep the application QoS between bounds. This framework shares many design concerns with our framework, although it has been targeted to the control of applications. OMG currently develops Real time CORBA facilities in the scope of the CORBA 3. 0 standard [Schmidt 00] These facilities allow one to manipulate some middleware characteristics that influence the QoS, such as, e.g. the properties of protocols underlying the ORB and the threading and priority polices applied to the handling of requests by server objects. These facilities are defined in terms of ....

D.C. Schmidt, F. Kuhns. An overview of the real-time CORBA specification. To appear in: IEEE Computer special issue on Object-oriented real-time distributed computing, June 2000.

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Douglas C. Schmidt and Fred Kuhns, "An Overview of the Real-time CORBA Specification," IEEE Computer Magazine, Special Issue on Object-oriented Real-time Computing, vol. 33, No. 6, June 2000.

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Schmidt D., Kuhns F., "An Overview of the Real-time CORBA Specification," IEEE Computer Magazine, June, 2000.

....Although RT CORBA is oriented towards applications with hard real time requirements, such as process control and weapons systems, it also supports applications with stringent soft real time requirements, such as telecommunication call processing. A comprehensive overview of RT CORBA appears in [4]. Implementations of RT CORBA including TAO [5] and ORBExpress (www.ois.com) have been evaluated positively [6] for their suitability to DRE systems that require end to end predictability and real time assurance. RTCORBA ORBs have also been used to . Improve situation awareness for prosecuting ....

Douglas C. Schmidt and Fred Kuhns, "An Overview of the Real-time CORBA Specification," IEEE Computer Magazine, Special Issue on Object-oriented Real-time Computing, vol. 33, no. 6, June 2000.

....5 discusses open issues and future search directions; and Section 6 presents concluding remarks. 2 Overview of Real time and Faulttolerant CORBA specifications This section provides a brief overview of the RT CORBA and FT CORBA specifications detailed descriptions of these standards appear in [21] and [19] respectively. ############# ################### ########### ############### ###### #### ######## ########## ###### ##### ######## ####### ######################### ######## ###### ### ######## Figure 1: ORB Endsystem Features for Real Time CORBA Overview of ....

Douglas C. Schmidt and Fred Kuhns, "An Overview of the Real-time CORBA Specification," IEEE Computer Magazine, Special Issue on Object-oriented Real-time Computing, vol. 33, no. 6, June 2000.

....######## Figure 1: Standard Capabilities in Real time CORBAORB Endsystems tem consists of network interfaces, an I O subsystem, other OS mechanisms, and ORB middleware capabilities that support end to end predictability for operations in fixed priority CORBA applications. These capabilities [3] include standard interfaces and QoS policies that allow applications to configure and control the following resources: # Processor resources via thread pools, priority mechanisms, and intraprocess mutexes # Communication resources via protocol properties and explicit bindings with ....

D. C. Schmidt and F. Kuhns, "An Overview of the Real-time CORBA Specification," IEEE Computer Magazine, Special Issue on Object-oriented Real-time Computing, vol. 33, June 2000.

....Computing (MIC) 1] Generative programming makes it possible to develop middleware systems that are amenable to customization of behavior and protocols (e.g. APIs) via automatic code generation and composition. Using a GP approach, the development of middleware, such as RTSJ or Real time CORBA [9], need not lead to a single implementation. Instead, it can provide a set of components and configuration knowledge that can be used to generated a specific implementation based on user defined specifications. If we consider the RTSJ scheduling API example, for instance, application developers ....

Schmidt, D.C., Kuhns, F.: An Overview of the Real-time CORBA Specification. IEEE Computer Magazine, Special Issue on Object-oriented Real-time Computing 33 (2000)

....adopted the Model Driven Architecture (MDA) 4] MDA standardizes the integration of the MIC paradigm with a variety of component middleware technologies, including CORBA CCM, J2EE, and COM . 1 RT CORBA. The increasing acceptance of the platform and vendor neutral OMG Real time CORBA (RT CORBA) [5] model into many distributed, real time, and embedded (DRE) systems, including avionics mission computing, software defined radios, radar systems, surface mount systems, and hot rolling mills. RT CORBA provides predictable, efficient, and fine grained control over system processing, communication, ....

Douglas C. Schmidt and Fred Kuhns, "An Overview of the Real-time CORBA Specification," IEEE Computer Magazine, Special Issue on Object-oriented Real-time Computing, vol. 33, no. 6, June 2000.

....work was funded in part by ATD, DARPA, SAIC, and Siemens. of distributed computing from application developers to middleware developers. It has been used successfully in largescale business systems where scalability, evolvability, and interoperability are essential for success. Real time CORBA [5] is a rapidly maturing DOC middleware technology standardized by the OMG that can simplify many challenges for DRE applications, just as CORBA has for large scale business systems. Real time CORBA is designed for applications with hard real time requirements, such as avionics mission computing ....

D. C. Schmidt and F. Kuhns, "An Overview of the Real-time CORBA Specification," IEEE Computer Magazine, Special Issue on Object-oriented Real-time Computing, vol. 33, June 2000.

....################## ######################### ######## ###### ### ######## Figure 1: Standard Capabilities in Real time CORBAORB Endsystems tems define standard capabilities that support end to end predictability for operations in fixed priority CORBA applications. These capabilities [3] include standard interfaces and QoS policies that allow applications to configure and control the following resources: # Processor resources via thread pools, priority mechanisms, and intraprocess mutexes # Communication resources via protocol properties and explicit bindings with ....

D. C. Schmidt and F. Kuhns, "An Overview of the Real-time CORBA Specification," IEEE Computer Magazine, Special Issue on Object-oriented Real-time Computing, vol. 33, June 2000.

....(2) exploiting advanced QoS features, such as controlling the ATM virtual circuit cell pacing rate [25] 2. OS scheduling mechanisms: ORBs exploit OS mechanisms to schedule application level activities end to end. The real time CORBA features in CORBA 2. 4 target fixed priority real time systems [26]. Thus, these mechanisms correspond to managing OS thread scheduling priorities. The Real time CORBA specification in CORBA 2.4 focuses on operating systems that allow applications to specify scheduling priorities and policies. For example, the real time extensions in IEEE POSIX 1003.1c [27] ....

D. C. Schmidt and F. Kuhns, "An Overview of the Real-time CORBA Specification," IEEE Computer Magazine, Special Issue on Object-oriented Real-time Computing, June 2000.

....middleware that allows objects to interoperate across networks without hard coding dependencies on their location, programming language, operating system platform, communication protocols and interconnects, and hardware characteristics. In 1998 the OMG adopted the Real time CORBA specification [Sch00a], which extends CORBA with features that allow DRE applications to reserve and manage CPU, memory, and networking resources. Real time CORBA implementations have been used in dozens of DoD combat systems, including avionics mission computing [Sha98] submarine combat control systems [DiPalma99] ....

Schmidt D., Kuhns F., "An Overview of the Real-time CORBA Specification," IEEE Computer Magazine, June, 2000.

....systems, have complex quality of service (QoS) requirements, such as stringent bandwidth, latency, jitter, and dependability needs. Historically, DRE systems were not well served by middleware like CORBA due to its lack of QoS support. The recent Real time CORBA (RT CORBA) 1. 0 specification [2, 3] in the CORBA 2.4 standard is an important step towards defining standards based, commercial off theshelf (COTS) middleware that can deliver end to end QoS support at multiple levels in DRE systems. As shown in Figure 1, RT CORBA ORB endsystems 1 define standard capa ########## ....

....properties and explicit bindings with non multiplexed connections and 1 An ORB endsystem consists of network interfaces, I O subsystem and other OS mechanisms, and ORB middleware capabilities. 1 # Memory resources via buffering requests in queues and bounding the size of thread pools. [3] presents an overview of the RT CORBA features and [4] explains how communication resources are configured and controlled efficiently in TAO [5] which is our highperformance, real time implementation of CORBA. There are two general strategies for implementing RTCORBA thread pools. The first ....

D. C. Schmidt and F. Kuhns, "An Overview of the Real-time CORBA Specification," IEEE Computer Magazine, Special Issue on Objectoriented Real-time Computing, June 2000.

....Request Broker Architecture (CORBA) Omg00] CORBA is distribution middleware that allows objects to interoperate across networks regardless of the language in which they were written or the OS platform on which they are deployed. In 1998 the OMG adopted the Real time CORBA (RTCORBA) specification [Sch00a], which extends CORBA with features that allow DRE applications to reserve and manage CPU, memory, and networking resources. RTCORBA implementations have been used in dozens of DRE systems, including telecom network management and call processing, online trading services, avionics mission ....

Schmidt D., Kuhns F., "An Overview of the Real-time CORBA Specification," IEEE Computer Magazine, June, 2000.

....(CORBA) Omg00] which is an open standard for distribution middleware that allows objects to interoperate across networks regardless of the language in which they were written or the platform on which they are deployed. In 1998 the OMG adopted the Real time CORBA (RT CORBA) specification [Sch00a], which extends CORBA with features that allow real time applications to reserve and manage CPU, memory, and networking resources. Sun s Java Remote Method Invocation (RMI) Wol96] which is distribution middleware that enables developers to create distributed Java to Java applications, in ....

Schmidt D., Kuhns F., "An Overview of the Real-time CORBA Specification," IEEE Computer Magazine, June, 2000.

....size, and variable power consumption [4] Distributed object computing middleware, such as CORBA, should be well suited to provide the core communication middleware for the distributed applications outlined above. For instance, recent additions to the CORBA specification, such as Real time CORBA [5] and CORBA Messaging [6] address many end to end quality of service (QoS) aspects. These specifications standardize interfaces and policies for defining and controlling various types of application QoS aspects. 1 Historically, however, the standard CORBA specification has not addressed ....

....2 Concluding Remarks Recent CORBA specifications define better support for QoS and configurability. In particular, the CORBA Component Model (CCM) 9] defines standard interfaces, policies, and services for structuring, integrating, and deploying CORBA components. Likewise, the Real time CORBA [5] and CORBA Messaging [6] specifications address many end toend quality of service (QoS) aspects. We believe, however, 1 The source code and documentation for TAO can be downloaded from www.cs.wustl.edu schmidt TAO.html. 2 NETWORK ORB RUN TIME IDL STUBS IDL SKELETON OS KERNEL HIGH SPEED ....

D. C. Schmidt and F. Kuhns, "An Overview of the Real-time CORBA Specification," Submitted to IEEE Computer Magazine, 2000.

....on memory footprint size and power consumption [5] DOC middleware based on CORBA should be well suited to provide the core communication middleware for the nextgeneration distributed applications outlined above. For instance, recent additions to the CORBA specification, such as Real time CORBA [6] and CORBA Messaging [7] address many end to end quality of service (QoS) properties. These specifications standardize interfaces and policies for defining and controlling various types of application QoS properties. Historically, however, the standard CORBA specification has not addressed ....

....define more comprehensive support for QoS, configurability, and automated server development. In particular, the CORBA Component Model (CCM) 10] defines standard interfaces, policies, and services for structuring, integrating, and deploying CORBA components. Likewise, the Real time CORBA [6] and CORBA Messaging [7] specifications address many end to end quality of7 service (QoS) properties. However, our experience using CORBA in a wide variety of projects suggests that the new generation of CORBA specifications will be unsuitable for an important class of QoSenabled applications ....

D. C. Schmidt and F. Kuhns, "An Overview of the Real-time CORBA Specification," IEEE Computer Magazine, Special Issue on Object-oriented Real-time Computing, June 2000.

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D. C. Schmidt and F. Kuhns. An Overview of the Real-Time CORBA Specification. IEEE Computer, 33(6):56--63, 2000.

No context found.

Schmidt DC, Kuhns F. An overview of the real-time CORBA specification. IEEE Comput (special issue on Object-Oriented Real-time Distributed Computing) 2000; 33(6):56--63.

No context found.

Douglas C. Schmidt and Fred Kuhns. An overview of the real-time CORBA specification. IEEE Computer, 33(6):56--63, June 2000.

No context found.

Schmidt DC, Kuhns F. An overview of the real-time CORBA specification. IEEE Comput (special issue on Object-Oriented Real-time Distributed Computing) 2000; 33(6):56--63.

No context found.

Douglas C. Schmidt and Fred Kuhns. An overview of the real-time CORBA specification. IEEE Computer, 33(6):56--63, June 2000.

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C. Schmidt and F. Kuhns. An overview of the Real-Time CORBA Specification. IEEE Computer, 33(6):56--63, June 2000.

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D. C. Schmidt and F. Kuhns. An overview of the real-time corba specification. IEEE Computer, 33(6):pp. 56--63, 2000.

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