1,391 research outputs found
Distributed debugging and tumult
A description is given of Tumult (Twente university multicomputer) and its operating system, along with considerations about parallel debugging, examples of parallel debuggers, and the proposed debugger for Tumult. Problems related to debugging distributed systems and solutions found in other distributed debuggers are discussed. The following are the main features of the debugger: it is event based, using a monitor for intercepting these events; record and reply are the main debugging techniques; preprocessing of events is done by programmable filters; the user interface is graphical, using grouping as the main abstraction mechanism. Parts of the debugger, as well as initial versions of the global and local event managers, have been implemented. A slow serial link between the front-end processor and the Tumult system has been replaced by a fast SCSI communication link. The user interface is partly textual, partly graphical. The languages used to implement the debugger are Modula-2 and C. The X Window System and OSF/Motif are used for the graphical user interfac
On debugging in a parallel system
In this paper a description is given of a partly implemented parallel debugger for the Twente University Multicomputer (TUMULT). The system's basic method for exchange of data is message passing. Experience has learned that most programming errors in application software are made in calls to the kernel and the interprocess communication. The debugger is intended to be used for locating bugs at this level in the application software. It is assumed that basic blocks of the debuggee can be debugged using a traditional sequential sourcelevel debugger
Active networks: an evolution of the internet
Active Networks can be seen as an evolution of the classical model of packet-switched networks. The traditional and ”passive” network model is based on a static definition of the network node behaviour. Active Networks propose an “active” model where the intermediate nodes (switches and routers) can load and execute user code contained in the data units (packets). Active Networks are a programmable network model, where bandwidth and computation are both considered shared network resources. This approach opens up new interesting research fields. This paper gives a short introduction of Active
Networks, discusses the advantages they introduce and presents the research advances in this field
A debugger for Modula-2 on the UNIX PC
Call number: LD2668 .R4 CMSC 1987 A23Master of ScienceComputing and Information Science
An operating system for future aerospace vehicle computer systems
The requirements for future aerospace vehicle computer operating systems are examined in this paper. The computer architecture is assumed to be distributed with a local area network connecting the nodes. Each node is assumed to provide a specific functionality. The network provides for communication so that the overall tasks of the vehicle are accomplished. The O/S structure is based upon the concept of objects. The mechanisms for integrating node unique objects with node common objects in order to implement both the autonomy and the cooperation between nodes is developed. The requirements for time critical performance and reliability and recovery are discussed. Time critical performance impacts all parts of the distributed operating system; e.g., its structure, the functional design of its objects, the language structure, etc. Throughout the paper the tradeoffs - concurrency, language structure, object recovery, binding, file structure, communication protocol, programmer freedom, etc. - are considered to arrive at a feasible, maximum performance design. Reliability of the network system is considered. A parallel multipath bus structure is proposed for the control of delivery time for time critical messages. The architecture also supports immediate recovery for the time critical message system after a communication failure
Motivating Time as a First Class Entity
In hard real-time applications, programs must not only be functionally correct but must also meet timing constraints. Unfortunately, little work has been done to allow a high-level incorporation of timing constraints into distributed real-time programs. Instead the programmer is required to ensure system timing through a complicated synchronization process or through low-level programming, making it difficult to create and modify programs. In this report, we describe six features that must be integrated into a high level language and underlying support system in order to promote time to a first class position in distributed real-time programming systems: expressibility of time, real-time communication, enforcement of timing constraints, fault tolerance to violations of constraints, ensuring distributed system state consistency in the time domain, and static timing verification. For each feature we describe what is required, what related work had been performed, and why this work does not adequately provide sufficient capabilities for distributed real-time programming. We then briefly outline an integrated approach to provide these six features using a high-level distributed programming language and system tools such as compilers, operating systems, and timing analyzers to enforce and verify timing constraints
Optimal performance of distributed simulation programs
Journal ArticleThis paper describes a technique to analyze the potential speedup of distributed simulation programs. A distributed simulation strategy is proposed which minimizes execution time through the use of an oracle to control the simulation. Because the strategy relies on an oracle, it cannot be used for practical simulations. However the strategy facilitates performance evaluations of distributed simulation strategies by providing a useful point of comparison and can be used to determine the suitability of specific applications for implementation on a parallel computer. Based on the proposed strategy, a tool has been developed to determine the maximum performance which can be achieved from a distributed simulation program. In this paper we describe the technique and its use in evaluating the parallelism available in distributed simulators of parallel computer systems
Training Probabilistic Spiking Neural Networks with First-to-spike Decoding
Third-generation neural networks, or Spiking Neural Networks (SNNs), aim at
harnessing the energy efficiency of spike-domain processing by building on
computing elements that operate on, and exchange, spikes. In this paper, the
problem of training a two-layer SNN is studied for the purpose of
classification, under a Generalized Linear Model (GLM) probabilistic neural
model that was previously considered within the computational neuroscience
literature. Conventional classification rules for SNNs operate offline based on
the number of output spikes at each output neuron. In contrast, a novel
training method is proposed here for a first-to-spike decoding rule, whereby
the SNN can perform an early classification decision once spike firing is
detected at an output neuron. Numerical results bring insights into the optimal
parameter selection for the GLM neuron and on the accuracy-complexity trade-off
performance of conventional and first-to-spike decoding.Comment: A shorter version will be published on Proc. IEEE ICASSP 201
EOS: A project to investigate the design and construction of real-time distributed embedded operating systems
The EOS project is investigating the design and construction of a family of real-time distributed embedded operating systems for reliable, distributed aerospace applications. Using the real-time programming techniques developed in co-operation with NASA in earlier research, the project staff is building a kernel for a multiple processor networked system. The first six months of the grant included a study of scheduling in an object-oriented system, the design philosophy of the kernel, and the architectural overview of the operating system. In this report, the operating system and kernel concepts are described. An environment for the experiments has been built and several of the key concepts of the system have been prototyped. The kernel and operating system is intended to support future experimental studies in multiprocessing, load-balancing, routing, software fault-tolerance, distributed data base design, and real-time processing
Using FoxNet for TCP/IP networking in ML/OS
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (leaves 42-43).by Alexander Vladimirov.M.Eng
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