[1990] Proceedings 11th Real-Time Systems Symposium

5-7 Dec. 1990

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  • Proceedings. 11th Real-Time Systems Symposium (Cat. No.90CH2933-0)

    Publication Year: 1990
    Request permission for commercial reuse | PDF file iconPDF (129 KB)
    Freely Available from IEEE
  • Resource reclaiming in real time

    Publication Year: 1990, Page(s):41 - 50
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (964 KB)

    Resource reclaiming refers to the problem of utilizing the resources left unused by a task when it executes in less than its worst-case computation time, or when a task is deleted from the current schedule. In dynamic real-time multiprocessor environments, resource reclaiming can be used to improve the average performance. Dynamic resource reclaiming algorithms must be effective in reclaiming unus... View full abstract»

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  • Language support for the Maruti real-time system

    Publication Year: 1990, Page(s):257 - 266
    Cited by:  Papers (15)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (732 KB)

    Maruti is a testbed for the design of time-driven hard real-time systems. It uses the technique of prescheduling, where the application is scheduled prior to execution and resources required by the application are reserved, in order to ensure that deadlines are met. A description is given of the features of MPL, a language for Maruti. MPL provides constructs for expressing time constraints, preced... View full abstract»

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  • Real-time system scenarios

    Publication Year: 1990, Page(s):214 - 225
    Cited by:  Papers (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (708 KB)

    Two computer systems are specified which are functionally similar to subsets of existing US Navy ship and submarine systems. The computer system descriptions represent no specific system either deployed, under development, or proposed. For each system, the computer system performance requirements and computer equipment selection criterion are given. The intent is to provide meaningful test problem... View full abstract»

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  • A robust group membership algorithm for distributed real-time systems

    Publication Year: 1990, Page(s):173 - 179
    Cited by:  Papers (18)  |  Patents (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (584 KB)

    An algorithm is presented by which nonfaulty processors of a group of fixed size will be able to maintain a consistent and timely knowledge of the group membership. The authors assume an architecture in which the broadcast network is accessed by some time domain multiplexing techniques where the exclusive right to transmit messages is granted to each processor once in every `cycle'. In an executio... View full abstract»

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  • Scheduling I/O requests with deadlines: A performance evaluation

    Publication Year: 1990, Page(s):113 - 124
    Cited by:  Papers (45)  |  Patents (10)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (992 KB)

    The I/O scheduling problem is examined in detail. The authors present a realistic model for studying this problem in the context of a system which executes real-time transactions. The model takes advantage of the fact that reading from the disk occurs before a transaction commits, while writing to the disk usually occurs after the transaction commits. New algorithms are presented that exploit this... View full abstract»

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  • Analysis of three contention protocols in distributed real-time systems

    Publication Year: 1990, Page(s):136 - 145
    Cited by:  Papers (10)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (824 KB)

    The probability of a station/node failing to deliver packets before their deadlines, called the probability of dynamic failure, P dyn, and the ∈-bounded delivery time, which is defined as the time period between the arrival of a packet and its delivery with probability greater than 1-∈, are important performance parameters for the communication subsystems of a distrib... View full abstract»

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  • The ARTS real-time object model

    Publication Year: 1990, Page(s):2 - 10
    Cited by:  Papers (18)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (744 KB)

    The authors present the motivation for using an object model for real-time operating systems, and describe the object model used in the ARTS kernel. A discussion is presented of the novel object classification and the priority inheritance properties which arise from this taxonomy. Various methods for implementing critical regions are described, and some guidelines as to the use of each are given View full abstract»

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  • Incremental garbage collection of concurrent objects for real-time applications

    Publication Year: 1990, Page(s):21 - 30
    Cited by:  Papers (3)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (688 KB)

    The authors show how to perform real-time automatic garbage collection of objects possessing their own thread of control. Beyond its interest as a novel real-time problem, the relevance of automatic management and concurrent objects to real-time applications is briefly discussed. The specific model of concurrent objects used in the paper is explained. A definition of real-time garbage collection i... View full abstract»

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  • Implementing a verifier for real-time systems

    Publication Year: 1990, Page(s):62 - 71
    Cited by:  Papers (13)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (876 KB)

    The SARTOR project has as one of its goals the development of an environment for the development of correct real-time systems. Modechart is a specification language for real-time systems developed as part of this project. Verify4 is an implementation of a verifier for certain classes of properties of systems specified using Modechart. The author describes the program Verify4 and addresses implemen... View full abstract»

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  • Applying compiler techniques to scheduling in real-time systems

    Publication Year: 1990, Page(s):247 - 256
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (800 KB)

    Worst-case scheduling techniques for real-time applications often result in sever underutilization of the processor resources since most tasks finish in much less time than their anticipated worst-case execution times. A description is presented of compiler-based techniques that classify the application code on the basis of predictability and monotonicity, introduce measurement code fragments at s... View full abstract»

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  • Fixed priority scheduling of periodic task sets with arbitrary deadlines

    Publication Year: 1990, Page(s):201 - 209
    Cited by:  Papers (283)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (616 KB)

    Consideration is given to the problem of fixed priority scheduling of period tasks with arbitrary deadlines. A general criterion for the schedulability of such a task set is given. Worst case bounds are given which generalize the C.L. Liu and J.W. Layland (1973) bound. The results are shown to provide a basis for developing predictable distributed real-time systems View full abstract»

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  • Agreeing on a leader in real-time [fault tolerant computer system]

    Publication Year: 1990, Page(s):166 - 172
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (568 KB)

    A method is devised for maintaining the continuing availability of a vital service in a real-time shared-memory multiprocessor fault-tolerant computer system. The essential characteristics of the service to be provided are given. The service can be correctly provided by any one operational processor acting alone. The job of selecting the processor to provide the service is the real-time leader ele... View full abstract»

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  • Specifying and verifying a real-time priority queue with modal algebra

    Publication Year: 1990, Page(s):300 - 310
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (780 KB)

    The authors use the modal primitive recursive (MPR) arithmetic to facilitate definition, composition, and reasoning about the very large-scale finite state machines that represent substantive real-time systems. The MPR arithmetic provides a language of integer-valued functions which allow for compact and intuitive specification of state machines without enumeration of state sets or transition func... View full abstract»

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  • Concurrency control in real-time databases by dynamic adjustment of serialization order

    Publication Year: 1990, Page(s):104 - 112
    Cited by:  Papers (42)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (720 KB)

    A new concurrency control algorithm for real-time database systems is proposed, by which real-time scheduling and concurrency control can be integrated. The algorithm is founded on a priority-based locking mechanism to support time-critical scheduling by adjusting the serialization order dynamically in favor of high priority transactions. Furthermore, it does not assume any knowledge about the dat... View full abstract»

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  • MRL: a real-time rule-based production system

    Publication Year: 1990, Page(s):267 - 276
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (720 KB)

    The response time analysis of rule-based expert systems is discussed. The rule-based production system MRL (macro-rule-based language) is introduced. MRL has been designed to facilitate more accurate analysis of the response times of programs while maintaining the flexibility and expressiveness of traditional production systems such as OPS5. Research on modular analysis of rule-based systems is de... View full abstract»

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  • Strategies for predictability in real-time data-flow architectures

    Publication Year: 1990, Page(s):226 - 235
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (824 KB)

    Consideration is given to the development of strategies for predictable performance in homogeneous multicomputer data-flow architectures operating in real-time. Algorithms are restricted to the class of large-grained, decision-free algorithms. The mapping of such algorithms onto the specified class of data-flow architectures is realized by a new marked graph model called ATAMM (algorithm to archit... View full abstract»

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  • Preemptively scheduling hard-real-time sporadic tasks on one processor

    Publication Year: 1990, Page(s):182 - 190
    Cited by:  Papers (264)  |  Patents (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (576 KB)

    Consideration is given to the preemptive scheduling of hard-real-time sporadic task systems on one processor. The authors first give necessary and sufficient conditions for a sporadic task system to be feasible (i.e., schedulable). The conditions cannot, in general, be tested efficiently (unless P=NP). They do, however, lead to a feasibility test that runs in efficient pseudo-polynomial time for a... View full abstract»

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  • On-line routing of real-time messages

    Publication Year: 1990, Page(s):126 - 135
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (772 KB)

    Whether it is possible to have an optimal online algorithm for unidirectional ring, out-tree, in-tree, bidirectional tree, and bidirectional ring networks is discussed. The problem is considered under various restrictions of four parameters-origin node, destination node, release time and deadline. For unidirectional ring, it is shown that no such algorithm can exist unless one of the four paramete... View full abstract»

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  • Real-time communication in multiple token ring networks

    Publication Year: 1990, Page(s):146 - 154
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (560 KB)

    A communication architecture and a dynamic control protocol are presented for real-time communication in multiple token ring networks. The network can be formed by multiple channels through bandwidth subdivision of a high-speed ring. A flexible preemption and dynamic load allocation scheme is developed which can reduce the lost percentage of critical packets and can maintain a high channel utiliza... View full abstract»

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  • Time capsules: an abstraction for access to continuous-media data

    Publication Year: 1990, Page(s):11 - 20
    Cited by:  Papers (12)  |  Patents (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (900 KB)

    The author presents the time capsule abstraction to describe how timed data shall be stored, exchanged, and accessed in a real-time system. When data are written into a time capsule, a time stamp and a duration are associated with the data item. When it is read, a time stamp is used to select the data item. The time capsule abstraction includes the notion of clocks that ensure periodic data access... View full abstract»

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  • Minimizing the number of late tasks with error constraint

    Publication Year: 1990, Page(s):32 - 40
    Cited by:  Papers (4)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (724 KB)

    The problem of minimizing the number of late tasks in the imprecise computation model is considered. Each task consists of two subtasks, mandatory and optional. A task is said to be on-time if its mandatory part is completed by its deadline; otherwise, it is said to be late. An on-time task incurs an error if its optional part is not computed by the deadline, and the error is simply the execution ... View full abstract»

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  • Scalability of a distributed real-time resource counter

    Publication Year: 1990, Page(s):51 - 59
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (672 KB)

    The authors address the topic of how to meet a real-time constraint as the load on a distributed system increases, without increasing the capacity of the individual processors. The application studied is a real-time resource counter with a probabilistic correctness criterion, and is motivated by the problem of implementing resource management in the telephone network. They introduce a model that c... View full abstract»

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  • Experiments with a program timing tool based on source-level timing schema

    Publication Year: 1990, Page(s):72 - 81
    Cited by:  Papers (31)  |  Patents (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (864 KB)

    A timing tool has been implemented for a subset of C as an initial experiment in validating a methodology for predicting the deterministic execution times of programs. The tool is based on formal timing schema that are defined for each source level construct (procedures, statements, expressions). The tool accepts a program and bounds for each loop, and produces predictions for best and worst case ... View full abstract»

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  • A tagged memory technique for recovery from transient errors in fault tolerant systems

    Publication Year: 1990, Page(s):312 - 321
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (648 KB)

    Recovery from transients is imperative to maintain necessary system reliability in the face of transient errors which have been estimated to occur at a rate of 5 to 100 times that of permanent failures. Excessive delays associated with recovery become a problem when as much as 512 Kbytes of RAM in the faulty processor must be restored while maintaining full functionality of 40-100 Hz iterative con... View full abstract»

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