1994 Proceedings Real-Time Systems Symposium

7-9 Dec. 1994

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Displaying Results 1 - 25 of 33
  • Emulating soft real-time scheduling using traditional operating system schedulers

    Publication Year: 1994, Page(s):292 - 298
    Cited by:  Papers (16)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (621 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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  • 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 (433 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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  • Supporting real-time traffic on Ethernet

    Publication Year: 1994, Page(s):282 - 286
    Cited by:  Papers (60)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (465 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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  • 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 (469 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.<<ETX>> View full abstract»

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  • Verifying an intelligent structural control system: a case study

    Publication Year: 1994, Page(s):271 - 275
    Cited by:  Papers (7)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (431 KB)

    Describes the formal verification of the timing properties of the design of an intelligent structural control system using the Concurrency Workbench, an automatic verification tool for finite-state processes. The high-level design of the system is first given in Modechart, a graphical specification language for real-time systems, and then translated into a temporal process algebra supported by the... View full abstract»

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  • Computing quantitative characteristics of finite-state real-time systems

    Publication Year: 1994, Page(s):266 - 270
    Cited by:  Papers (26)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (553 KB)

    Presents a general method for computing quantitative information about finite-state real-time systems. We have developed algorithms that compute exact bounds on the delay between two specified events and on the number of occurrences of an event in a given interval. This technique allows us to determine performance measures such as schedulability, response time, and system load. Our algorithms prod... 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 (160)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (553 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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  • 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 (989 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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  • Probabilistic bounds on message delivery for the totem single-ring protocol

    Publication Year: 1994, Page(s):238 - 248
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1084 KB)

    For fault-tolerant real-time distributed systems, the probability that a message is not delivered within its real-time deadline must be small enough that it does not adversely affect system reliability. The authors investigate the delivery of messages for the totem protocol, a reliable ordered broadcast protocol that the authors have developed for fault-tolerant distributed systems with physical b... View full abstract»

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  • On-line scheduling to maximize task completions

    Publication Year: 1994, Page(s):228 - 236
    Cited by:  Papers (27)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (769 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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  • Dynamic end-to-end guarantees in distributed real time systems

    Publication Year: 1994, Page(s):216 - 227
    Cited by:  Papers (82)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1249 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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  • 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 (822 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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  • Guaranteeing end-to-end timing constraints by calibrating intermediate processes

    Publication Year: 1994, Page(s):192 - 203
    Cited by:  Papers (52)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1161 KB)

    Presents a comprehensive design methodology for guaranteeing end-to-end requirements of real-time systems. Applications are structured as a set of process components connected by asynchronous channels, in which the endpoints are the system's external inputs and outputs. Timing constraints are then postulated between these inputs and outputs, they express properties such as end-to-end propagation d... View full abstract»

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  • Deterministic upperbounds of the worst-case execution times of cached programs

    Publication Year: 1994, Page(s):182 - 191
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (871 KB)

    Proposes techniques to derive the worst-case execution time (WCET) of cached programs. We focus on the analysis of one single program run on a direct-mapped cache, where no external interference could occur. The analysis complexity of the WCET of (un)cached programs is NP-complete. For nested loops, we derive some sufficient conditions in deriving the deterministic bounds of their WCET. These suff... View full abstract»

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  • Bounding worst-case instruction cache performance

    Publication Year: 1994, Page(s):172 - 181
    Cited by:  Papers (79)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1019 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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  • ARINC 659 scheduling: problem definition

    Publication Year: 1994, Page(s):165 - 169
    Cited by:  Papers (21)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (472 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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  • Applying RMA to improve a high-speed, real time data acquisition system

    Publication Year: 1994, Page(s):159 - 164
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (551 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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  • A solution to an automotive control system benchmark

    Publication Year: 1994, Page(s):154 - 158
    Cited by:  Papers (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (570 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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  • Response-time bounds of rule-based programs under rule priority structure

    Publication Year: 1994, Page(s):142 - 151
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (878 KB)

    A key index of the performance of a rule-based program used in real-time monitoring and control is its response time, defined by the maximum number of rule firings before a fixed point of the program is reached from a start state. Previous work in computing the response-time bounds for rule-based programs assumes that if two rules are enabled, then either one of them may be scheduled for firing. T... 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 (971 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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  • The generalized railroad crossing: a case study in formal verification of real-time systems

    Publication Year: 1994, Page(s):120 - 131
    Cited by:  Papers (42)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1292 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.<<E... View full abstract»

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  • Compiler transformations for speculative execution in a real-time system

    Publication Year: 1994, Page(s):109 - 117
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (721 KB)

    Deterministic worst-case execution to satisfy hard real-time constraints, and speculative execution with rollback to improve average-case throughput, appear to lie on opposite ends of a spectrum of performance requirements and strategies. Nonetheless, we show there are situations in which speculative execution can probably improve the performance of a hard real-time system, either by improving ave... View full abstract»

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  • An accurate worst case timing analysis technique for RISC processors

    Publication Year: 1994, Page(s):97 - 108
    Cited by:  Papers (45)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1200 KB)

    An accurate and safe estimation of a task's worst case execution time (WCET) is crucial for reasoning about the timing properties of real-time systems. In RISC processors, the execution time of a program construct (e.g., a statement) is affected by various factors such as cache hits/misses and pipeline hazards, and these factors impose serious problems in analyzing the WCETs of tasks. To analyze t... 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 (15)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1294 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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  • 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 (962 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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