A report discusses the continuing development of a scalable multiprocessor computing system for hard real-time applications aboard a spacecraft. "Hard real-time applications" signifies applications, like real-time radar signal processing, in which the data to be processed are generated at "hundreds" of pulses per second, each pulse "requiring" millions of arithmetic operations. In these applications, the digital processors must be tightly integrated with analog instrumentation (e.g., radar equipment), and data input/output must be synchronized with analog instrumentation, controlled to within fractions of a microsecond. The scalable multiprocessor is a cluster of identical commercial-off- the-shelf generic DSP (digital-signal- processing) computers plus generic interface circuits, including analog-to-digital converters, all controlled by software. The processors are computers interconnected by high-speed serial links. Performance can be increased by adding hardware modules and correspondingly modifying the software. Work is distributed among the processors in a parallel or pipeline fashion by means of a flexible master/slave control and timing scheme. Each processor operates under its own local clock; synchronization is achieved by broadcasting master time signals to all the processors, which compute offsets between the master clock and their local clocks.
This work was done by James Lux, Minh Lang, Kouji Nishimoto, Douglas Clark, Dorothy Stosic, Alex Bachmann, William Wilkinson, and Richard Steffke of Caltech for NASA's Jet Propulsion Laboratory . The software used in this innovation is available for commercial licensing. Please contact Don Hart of the California Institute of Technology at (818) 393-3425. Refer to NPO-40270.
This Brief includes a Technical Support Package (TSP).
Scalable Multiprocessor for High-Speed Computing in Space
(reference NPO40270) is currently available for download from the TSP library.
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Overview
The document titled "Technical Support Package for Scalable Multiprocessor for High-Speed Computing in Space" (NPO-40270) is a NASA Tech Brief that outlines advancements in scalable multiprocessor technology aimed at enhancing high-speed computing capabilities for space applications. It emphasizes the need for efficient processing systems that can handle the increasing complexity and data rates associated with modern aerospace missions.
Key highlights of the document include:
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Design Philosophy: The document advocates for reducing development risks by keeping functions simple and hardware generic. This approach allows for early integration and development using simple, generic hardware, which is crucial for timely project execution.
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Interprocessor Communication: It discusses the challenges of interprocessor communications, particularly in applications requiring low data rates and high timing accuracy. The document outlines various communication methods, including shared memory for tightly coupled systems with high bandwidth and communication links (both parallel and serial) for looser coupling with medium bandwidth.
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Programmable DSP Approach: The document details the use of programmable Digital Signal Processors (DSPs) for handling baseband signals, timing signals, processed science data, commands, and housekeeping telemetry. It highlights the importance of timing-critical functions being managed within the DSP to ensure accurate and efficient processing.
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System Design Considerations: The document emphasizes the importance of designing around existing boards from various vendors, allowing for flexibility in choosing build/buy options at the slice level. This intimate knowledge of system slices ensures software and hardware compatibility, leading to a more predictable integration and testing flow.
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Scalability and Performance: The scalable multiprocessor design is intended to provide a well-defined performance-to-cost function, enabling meaningful trade-offs during the formulation phase of projects. This scalability is crucial for adapting to the evolving demands of space missions.
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Technical Support and Resources: The document provides information on additional resources available through NASA's Scientific and Technical Information (STI) Program Office, offering further assistance and access to a variety of publications related to aerospace technology.
In summary, this technical support package serves as a comprehensive guide for leveraging scalable multiprocessor technology in high-speed computing for space applications, addressing design philosophies, communication challenges, and the importance of programmability in DSPs to meet the rigorous demands of aerospace missions.
