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

A Novel Approach to Pci Simulation Using ScriptSim

In recent years, the Peripheral Component Interconnect (PCI) has become one of the most widely used bus architectures in modern computers. Simulation of the PCI bus, however, has been limited in both research and development. Current commercial PCI simulation software is designed towards compliance and verification testing rather than accurately mimicking PCI bus systems. In addition, most PCI simulation software is inflexible and offers no graphical user interface, instead relying on text files for configuration. This paper presents a novel approach to PCI simulation using ScriptSim, an open-source PCI simulation tool that supports all the features offered by the PCI Local Specification Version 2.2. In addition to extending ScriptSim to include PCI-X functionality and a web-based graphical interface, we introduce techniques that allow us to accurately simulate real-world systems

Rewriteable optical disk recorder development

A NASA program to develop a high performance (high rate, high capability) rewriteable optical disk recorder for spaceflight applications is presented. An expandable, adaptable system concept is proposed based on disk Drive modules and a modular Controller. Drive performance goals are 10 gigabyte capacity are up to 1.8 gigabits per second rate with concurrent I/O, synchronous data transfer, and 2 to 5 years operating life in orbit. Technology developments, design concepts, current status, and future plans are presented

Telemetry downlink interfaces and level-zero processing

The technical areas being investigated are as follows: (1) processing of space to ground data frames; (2) parallel architecture performance studies; and (3) parallel programming techniques. Additionally, the University administrative details and the technical liaison between New Mexico State University and Goddard Space Flight Center are addressed

Proving sequential consistency by model checking

Sequential consistency is a multiprocessor memory model of both practical and theoretical importance. Unfortunately, the general problem of verifying that a finitestate protocol implements sequential consistency is undecidable, and in practice, validating that a real-world, finitestate protocol implements sequential consistency is very time-consuming and costly. In this work, we show that for memory protocols that occur in practice, a small amount of manual effort can reduce the problem of verifying sequential consistency into a verification task that can be discharged automatically via model checking. Furthermore, we present experimental results on a substantial, directorybased cache coherence protocol, which demonstrate the practicality of our approach.

Rate monotonic analysis for real-time systems

Rate monotonic analysis (RMA), a mathematical approach that helps ensure that a real-time system meets its performance requirements, is discussed. It does so through a collection of quantitative methods and algorithms that let engineers understand, analyze, and predict the timing behavior of their designs. An application of RMA to an air traffic control system is described. Document type: Repor

A Feature Taxonomy and Survey of Synchronization Primitive Implementations

Coordinated Science Laboratory was formerly known as Control Systems LaboratoryNCR Corporatio

Development of PCI Embedded Card Useful for Microcontroller Trainer

Not availabl