Spacelab system analysis: A study of the Marshall Avionics System Testbed (MAST)

An analysis of the Marshall Avionics Systems Testbed (MAST) communications requirements is presented. The average offered load for typical nodes is estimated. Suitable local area networks are determined

Spacelab system analysis: A study of communications systems for advanced launch systems

An analysis of the required performance of internal avionics data bases for future launch vehicles is presented. Suitable local area networks that can service these requirements are determined

Guaranteed bandwidth implementation of message passing interface on workstation clusters

Due to their wide availability, networks of workstations (NOW) are an attractive platform for parallel processing. Parallel programming environments such as Parallel Virtual Machine (PVM), and Message Passing Interface (MPI) offer the user a convenient way to express parallel computing and communication for a network of workstations. Currently, a number of MPI implementations are available that offer low (average ) latency and high bandwidth environments to users by utilizing an efficient MPI library specification and high speed networks. In addition to high bandwidth and low average latency requirements, mission critical distributed applications, audio/video communications require a completely different type of service, guaranteed bandwidth and worst case delays (worst case latency) to be guaranteed by underlying protocol. The hypothesis presented in this paper is that it is possible to provide an application a low level reliable transport protocol with performance and guaranteed bandwidth as close to the hardware on which it is executing. The hypothesis is proven by designing and implementing a reliable high performance message passing protocol interface which also provides the guaranteed bandwidth to MPI and to mission critical distributed MPI applications. This protocol interface works with the Fiber Distributed Data Interface (FDDI) driver which has been designed and implemented for Performance Technology Inc. commercial high performance FDDI product, the Station Management Software 7.3, and the ADI / MPICH (Argonne National Laboratory and Mississippi State University\u27s free MPI implementation)

Advanced information processing system: The Army fault tolerant architecture conceptual study. Volume 2: Army fault tolerant architecture design and analysis

Described here is the Army Fault Tolerant Architecture (AFTA) hardware architecture and components and the operating system. The architectural and operational theory of the AFTA Fault Tolerant Data Bus is discussed. The test and maintenance strategy developed for use in fielded AFTA installations is presented. An approach to be used in reducing the probability of AFTA failure due to common mode faults is described. Analytical models for AFTA performance, reliability, availability, life cycle cost, weight, power, and volume are developed. An approach is presented for using VHSIC Hardware Description Language (VHDL) to describe and design AFTA's developmental hardware. A plan is described for verifying and validating key AFTA concepts during the Dem/Val phase. Analytical models and partial mission requirements are used to generate AFTA configurations for the TF/TA/NOE and Ground Vehicle missions

Performance Improvements for FDDI and CSMA/CD Protocols

The High-Performance Computing Initiative from the White House Office of Science and Technology Policy has defined 20 major challenges in science and engineering which are dependent on the solutions to a number of high-performance computing problems. One of the major areas of focus of this initiative is the development of gigabit rate networks to be used in environments such as the space station or a National Research and Educational Network (NREN). The strategy here is to use existing network designs as building blocks for achieving higher rates, with the ultimate goal being a gigabit rate network. Two strategies which contribute to achieving this goal are examined in detail.1 FDDI2 is a token ring network based on fiber optics capable of a 100 Mbps rate. Both media access (MAC) and physical layer modifications are considered. A method is presented which allows one to determine maximum utilization based on the token-holding timer settings. Simulation results show that employing the second counter-rotating ring in combination with destination removal has a multiplicative effect greater than the effect which either of the factors have individually on performance. Two 100 Mbps rings can handle loads in the range of 400 to 500 Mbps for traffic with a uniform distribution and fixed packet size. Performance is dependent on the number of nodes, improving as the number increases. A wide range of environments are examined to illustrate robustness, and a method of implementation is discussed

Space Station Freedom data management system growth and evolution report

The Information Sciences Division at the NASA Ames Research Center has completed a 6-month study of portions of the Space Station Freedom Data Management System (DMS). This study looked at the present capabilities and future growth potential of the DMS, and the results are documented in this report. Issues have been raised that were discussed with the appropriate Johnson Space Center (JSC) management and Work Package-2 contractor organizations. Areas requiring additional study have been identified and suggestions for long-term upgrades have been proposed. This activity has allowed the Ames personnel to develop a rapport with the JSC civil service and contractor teams that does permit an independent check and balance technique for the DMS

Software Tool Evaluation Methodology

The recent development of parallel and distributed computing software has introduced a variety of software tools that support several programming paradigms and languages. This variety of tools makes the selection of the best tool to run a given class of applications on a parallel or distributed system a non-trivial task that requires some investigation. We expect tool evaluation to receive more attention as the deployment and usage of distributed systems increases. In this paper, we present a multi-level evaluation methodology for parallel/distributed tools in which tools are evaluated from different perspectives. We apply our evaluation methodology to three message passing tools viz Express, p4, and PVM. The approach covers several important distributed systems platforms consisting of different computers (e.g., IBM-SP1, Alpha cluster, SUN workstations) interconnected by different types of networks (e.g., Ethernet, FDDI, ATM)

Future benefits and applications of intelligent on-board processing to VSAT services

The trends and roles of VSAT services in the year 2010 time frame are examined based on an overall network and service model for that period. An estimate of the VSAT traffic is then made and the service and general network requirements are identified. In order to accommodate these traffic needs, four satellite VSAT architectures based on the use of fixed or scanning multibeam antennas in conjunction with IF switching or onboard regeneration and baseband processing are suggested. The performance of each of these architectures is assessed and the key enabling technologies are identified

Performance analysis of the Fiber distributed data interface (FDDI) network using petri nets and SPNP software package

The main purpose of this thesis is to model a Fiber Distributed Data Interface (FDDI) Network using Petri Nets, and to analyze its performance with the help of the SPNP software package. The verification of a communication protocol, by modeling it as a discrete-event system using Petri Nets is a new approach. The correlation between the throughput rate, voice and data throughput, and the parameters of the system, such as the network load and the network speed are investigated. An overview of the Fiber Distributed Data Interface is provided, along with its network protocol and the limitations of its operating parameters. A proposed Petri Net approach is then introduced. Finally, the effect of the network latency and load on the network\u27s overall performance is derived. A method for minimum delay is also proposed, and demonstrated with examples and computation results