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1994 Proceedings Real-Time Systems Symposium

7-9 Dec. 1994

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Displaying Results 1 - 25 of 33
  • Proceedings Real-Time Systems Symposium

    Publication Year: 1994
    Request permission for commercial reuse | PDF file iconPDF (77 KB)
    Freely Available from IEEE
  • Scaling and performance of a priority packet queue for real-time applications

    Publication Year: 1994, Page(s):56 - 62
    Cited by:  Papers (2)  |  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (632 KB)

    Real-time multiprocessor applications are typically characterized by hard deadlines which severely constrain interprocessor communications. Contention for communication resources and the use of first-in-first-out (FIFO) buffering can introduce priority inversion, resulting in missed deadlines. This paper investigates the scaling and performance of a novel 1.2 μm CMOS Priority Packet Queue (PPQ)... View full abstract»

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  • Efficient aperiodic service under earliest deadline scheduling

    Publication Year: 1994, Page(s):2 - 11
    Cited by:  Papers (100)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (740 KB)

    We present four new on-line algorithms for servicing soft aperiodic requests in real-time systems, where a set of hard periodic tasks is scheduled using the Earliest Deadline First (EDF) algorithm. All the proposed solutions can achieve full processor utilization and enhance aperiodic responsiveness, still guaranteeing the execution of the periodic tasks. Operation of the algorithms, performance, ... View full abstract»

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  • A priority forwarding router chip for real-time interconnection networks

    Publication Year: 1994, Page(s):63 - 73
    Cited by:  Papers (4)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (736 KB)

    The design and performance of a priority forwarding router chip are presented. The chip has four input and four output ports, employs clock-synchronized packet switching, and facilitates 32-bit priority arbitration by means of a priority forwarding scheme that prevents priority inversion and enables accurate priority control within a network. Packets are of a fixed size, each having three 38-bit s... View full abstract»

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  • Mechanisms for enhancing the flexibility and utility of hard real-time systems

    Publication Year: 1994, Page(s):12 - 21
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (900 KB)

    Adaptive and dynamic behaviour is seen as one of the key characteristics of next generation hard real-time systems. Whilst fixed priority pre-emptive scheduling is rapidly becoming a de facto standard in real-time systems engineering, it remains inflexible in its purest form. One method of increasing flexibility is via the incorporation of optional components into processes with hard deadlines. Su... View full abstract»

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  • Modeling DSP operating systems for multimedia applications

    Publication Year: 1994, Page(s):287 - 291
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (372 KB)

    Real-time scheduling theory attempts to guarantee that a real-time task set will always meet its deadlines. Real-time systems are typically implemented via real-time operating systems (RTOSs). However, there currently exists a wide gap between real-time scheduling theory and the reality of RTOS implementation. Bridging the gap requires effort on two fronts. First, real-time scheduling theory must ... View full abstract»

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  • Multiple route real-time channels in packet-switched networks

    Publication Year: 1994, Page(s):74 - 83
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (824 KB)

    A real-time channel is a communication mechanism commonly used to guarantee timely delivery of messages between two nodes of a distributed system. It is established at the request of an application task. In the request, the task specifies its worst-case traffic pattern and the required timing constraints. The system accepts the request only if it can guarantee the requested timing constraints with... View full abstract»

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  • ARINC 659 scheduling: problem definition

    Publication Year: 1994, Page(s):165 - 169
    Cited by:  Papers (20)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (412 KB)

    Honeywell is completing integration of the new Boeing 777 integrated Airplane Information Management System (AIMS). AIMS functions range from hard real-time to non-real-time, include flight-critical and non-essential functions, and must all reside on the same distributed multiprocessor system. This system, based on Aeronautical Radio Inc's ARINC 659 specification, allows for high resource utilizat... View full abstract»

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  • Algorithms for scheduling hard aperiodic tasks in fixed-priority systems using slack stealing

    Publication Year: 1994, Page(s):22 - 33
    Cited by:  Papers (34)  |  Patents (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1032 KB)

    This paper discusses the problem of jointly scheduling hard deadline periodic tasks and hard deadline aperiodic tasks using fixed priority methods. The approach is based on the slack stealing algorithm developed by the authors, and it assumes that the periodic deadlines must all be met. The paper develops a hard aperiodic acceptance test algorithm for guaranteeing tasks at any priority level, and ... View full abstract»

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  • On-line scheduling to maximize task completions

    Publication Year: 1994, Page(s):228 - 236
    Cited by:  Papers (22)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (648 KB)

    The problem of uniprocessor scheduling under conditions of overload is investigated. The system objective is to maximize the number of tasks that complete by their deadlines. For this performance metric it is shown that, in general, any on-line algorithm may perform arbitrarily poorly as compared to a clairvoyant scheduler. Restricted instances of the general problem for which on-line schedulers r... View full abstract»

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  • Modeling and analysis of real-time Ada tasking programs

    Publication Year: 1994, Page(s):132 - 141
    Cited by:  Papers (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (832 KB)

    Proposes a model for real-time Ada tasking programs that naturally represents such features as processor sharing, priority preemption, and process suspension. We describe a semi-decision procedure for proving properties of the model that uses linear programming to determine the feasibility of paths explored during a state-space search of the program. We demonstrate the feasibility of this procedur... View full abstract»

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  • Emulating soft real-time scheduling using traditional operating system schedulers

    Publication Year: 1994, Page(s):292 - 298
    Cited by:  Papers (15)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (528 KB)

    Real-time scheduling algorithms are usually only available in the kernels of real-time operating systems, and not in more general purpose operating systems, like Unix. For some soft real-time problems, a traditional operating system may be the development platform of choice. This paper addresses methods of emulating real-time scheduling algorithms on top of standard time-share schedulers. We exami... View full abstract»

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  • Busy-idle profiles and compact task graphs: compile-time support for interleaved and overlapped scheduling of real-time tasks

    Publication Year: 1994, Page(s):86 - 96
    Cited by:  Papers (14)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1124 KB)

    A new task graph representation, namely the compact task graph (CTG) is developed to aid in the scheduling of a set of communicating periodic real-time tasks. This representation exposes the potential for parallelism across tasks as well as the idle times that may be encountered within a task. Therefore using a CTG a real-time scheduler can generate schedules that are able to meet deadlines by int... View full abstract»

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  • Analysing real-time communications: controller area network (CAN)

    Publication Year: 1994, Page(s):259 - 263
    Cited by:  Papers (146)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (476 KB)

    The increasing use of communication networks in time-critical applications presents engineers with fundamental problems with the determination of response times of communicating distributed processes. Although there has been some work on the analysis of communication protocols, most of this is for idealised networks. Experience with single-processor scheduling analysis has shown that models which ... View full abstract»

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  • Bounding worst-case instruction cache performance

    Publication Year: 1994, Page(s):172 - 181
    Cited by:  Papers (69)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (876 KB)

    The use of caches poses a difficult tradeoff for architects of real-time systems. While caches provide significant performance advantages, they have also been viewed as inherently unpredictable, since the behavior of a cache reference depends upon the history of the previous references. The use of caches is only suitable for real-time systems if a reasonably tight bound on the performance of progr... View full abstract»

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  • Resource management for continuous multimedia database applications

    Publication Year: 1994, Page(s):46 - 54
    Cited by:  Papers (7)  |  Patents (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (684 KB)

    The uniqueness of continuous multimedia database applications lies in the fact that they require system support steady flow of media access data. In this paper we address the problem of system resource management for such applications. We introduce a session-based scheduling paradigm that, unlike traditional task scheduling, enables scheduling of all processing entities (threads, I/O processes, an... View full abstract»

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  • Supporting real-time traffic on Ethernet

    Publication Year: 1994, Page(s):282 - 286
    Cited by:  Papers (58)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (396 KB)

    Ethernet has been the dominant local area network architecture in the last decade, and we believe that it will continue to be so because of its cost-effectiveness and the availability of higher-bandwidth Ethernets. We propose and evaluate a software-based protocol called RETHER (Real-time ETHERnet) that provider real-time performance guarantees to multimedia applications without modifying existing... View full abstract»

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  • Applying RMA to improve a high-speed, real time data acquisition system

    Publication Year: 1994, Page(s):159 - 164
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (472 KB)

    Unlike other real-time systems, data acquisition applications spend most of their time performing synchronous and asynchronous I/O operations. This fact, that affects the tasks' abilities to meet deadlines, can be modelled with some extensions to the classic rate monotonic schedulability test. In this paper, we address this issue by investigating a case study for the application of rate monotonic ... View full abstract»

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  • Dynamic end-to-end guarantees in distributed real time systems

    Publication Year: 1994, Page(s):216 - 227
    Cited by:  Papers (77)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1088 KB)

    Many distributed real-time applications are structured as a set of processes communicating through synchronous channels. Unfortunately, process interactions and especially synchronous communications make the problem of predictably scheduling the tasks more complex. In distributed systems the local and remote tasks as well as the messages over the network must be properly scheduled and synchronized... View full abstract»

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  • The generalized railroad crossing: a case study in formal verification of real-time systems

    Publication Year: 1994, Page(s):120 - 131
    Cited by:  Papers (38)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1120 KB)

    A new solution to the generalized railroad crossing problem, based on timed automata, invariants and simulation mappings, is presented and evaluated. The solution shows formally the correspondence between four system descriptions: an axiomatic specification, an operational specification, a discrete system implementation, and a system implementation that works with a continuous gate model View full abstract»

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  • Real-time communication services in a DQDB network

    Publication Year: 1994, Page(s):249 - 258
    Cited by:  Papers (6)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (856 KB)

    Addresses the problem of transmitting real-time periodic traffic in a DQDB network. In a DQDB network, connection-oriented isochronous services use the pre-arbitrated (PA) access. The standard specifies that isochronous connections must have guaranteed periodic bandwidth but mechanisms to provide it, such as the slot allocation scheme, are not described. We propose a real-time service provider (RT... View full abstract»

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  • Timeliness via speculation for real-time databases

    Publication Year: 1994, Page(s):36 - 45
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (868 KB)

    Various concurrency control algorithms differ in the time when conflicts are detected, and in the way they are resolved. Pessimistic (PCC) protocols detect conflicts as soon as they occur and resolve them using blocking. Optimistic (OCC) protocols detect conflicts at transaction commit time and resolve them using rollbacks. For real-time databases, blockages and rollbacks are hazards that increase... View full abstract»

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  • Flexible real-time SQL transactions

    Publication Year: 1994, Page(s):276 - 280
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (400 KB)

    Presents flexible transaction structuring capabilities that allow related ACID properties (atomicity, consistency, isolation and durability) for better support of real-time transactions. The specification of these flexible transaction structures is demonstrated through proposed extensions to the standard SQL database language View full abstract»

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  • A solution to an automotive control system benchmark

    Publication Year: 1994, Page(s):154 - 158
    Cited by:  Papers (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (492 KB)

    The Society of Automotive Engineers (SAE) has recently published a set of requirements and a control benchmark which is able to compare the effectiveness of new protocol proposals for safety-critical automotive systems. This paper presents a solution to this benchmark problem that is based on the Time Triggered Protocol (TTP). TTP integrates all services required for the implementation of fault-to... View full abstract»

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  • Scheduling adaptive tasks in real-time systems

    Publication Year: 1994, Page(s):206 - 215
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (708 KB)

    In a real-time system, a repetitive task can be scheduled as a periodic task or an adaptive task to meet its timing requirement. For a periodic task, the deadline is always one period interval from the ready time and the current deadline will become the ready time for the next task instance. Whereas for an adaptive task, the deadline is set to one period interval from the completion of the previou... View full abstract»

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