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DCS Overview

DCS Overview. MCS/DCS Technical Interchange Meeting August, 2000. The “Mission”.

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DCS Overview

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  1. DCS Overview MCS/DCS Technical Interchange Meeting August, 2000

  2. The “Mission” “The DCS shall provide the infrastructure to support the operation of facility instruments on SOFIA using best current knowledge and tools, and supporting continuous improvement in an efficient, extensible, and modular architecture.” -- DCS CoDR, June 1999. SOFIA Data Cycle System: Overview

  3. DCS Requirements “The recommendations of the CoDR committee are the top level requirements for the DCS.” -- DCS PDR, March 2000. SOFIA Data Cycle System: Overview

  4. DCS Requirements • The DCS shall record and archive all data necessary for complete analysis, calibration and future access to observational data obtained with the FSIs. • The DCS shall support a select number of observing modes with pipeline reduction, including quicklook analysis, for each of the FSIs. SOFIA Data Cycle System: Overview

  5. DCS Requirements • The DCS shall provide on-line documentation necessary for the GI to propose and carry out observations with the FSIs. • The DCS shall be implemented as a system of distributed modules, integrated by an extensible hardware and software infrastructure. SOFIA Data Cycle System: Overview

  6. DCS Requirements Functionality mandated by SOFIA leaders covers two functional domains: • SOFIA: Data acquisition from live instrument, fast in-flight reduction (“quicklook”). • SSMOC: Data acquisition from simulators and other external sources, full reduction of FSI data. SOFIA Data Cycle System: Overview

  7. DCS Requirements Goal: Avoid building two separate systems if at all possible. Observation: The functional role is the same, only the algorithms and equipment varies. Solution: Two DCS systems, one in SOFIA and one at SSMOC. Each instance of the DCS has the pipelines and interfaces needed for its environment. The core DCS is identical and invariant. SOFIA Data Cycle System: Overview

  8. DCS Design Goals “The DCS must support and benefit from continuous improvement, both in itself and within the SOFIA program, over a twenty year lifetime.” -- DCS PDR, March 2000. SOFIA Data Cycle System: Overview

  9. DCS Design Goals The DCS design must be: • Modular • Extensible • Maintainable This is the heart of “continuous improvement.” -- DCS PDR, March 2000. SOFIA Data Cycle System: Overview

  10. DCS Design Goals: Modular • The DCS must not be a monolithic program. • The DCS must not be limited to a single system. • The DCS shall be a collection of small independent services, residing on one or more machines, providing functionality “as needed”. SOFIA Data Cycle System: Overview

  11. DCS Design Goals: Extensible • The DCS must support the easy incorporation of new procedures and techniques to its repertoire. • The DCS will provide for the safe test and evaluation of new components, while maintaining access to established “proven components”. SOFIA Data Cycle System: Overview

  12. DCS Design Goals: Maintainable • The DCS must not be tied to any specific vendor or platform. • The DCS must be based on open, widely available standards and technologies. • The DCS must be well documented, both in design and implementation. SOFIA Data Cycle System: Overview

  13. DCS Base Technologies Technologies on which the DCS system is based: • Distribution of and communication between objects across a system. (CORBA) • Extensible and flexible exchange of information, both in data and documentation. (XML) SOFIA Data Cycle System: Overview

  14. DCS Subsystems DCS Storage Data Acquisition User Interaction Layer Task Library Data Reduction SOFIA Data Cycle System: Overview

  15. DCS Subsystems: User Interaction • Common interface to all DCS resources • The “DCS experience” is customizable on a per user basis without affecting the rest of the DCS • Leverages off the web and related tools • Access regardless of geographic location • Relies only on commonly available technology at user’s end (e.g. web browser) SOFIA Data Cycle System: Overview

  16. DCS Subsystems: User Interaction DCS Storage Data Acquisition User profile User Interaction Layer Task Library Data Reduction User Proxy Requests and Responses SOFIA Data Cycle System: Overview

  17. DCS Subsystems: Task Library • Home to all core functionality on user’s behalf. • Can build on simple tasks to provide sophisticated sequences of actions. • Easily extended with new activities and procedures. • “Once you know how to do it, we can automate it.” SOFIA Data Cycle System: Overview

  18. DCS Subsystems: Task Library DCS Storage Data Acquisition User Interaction Layer Initiate, monitor, and control data acquisition Storage access is unique to task’s needs Task Library Data Reduction User Proxy Requests and Responses Initiate and monitor data reduction SOFIA Data Cycle System: Overview

  19. DCS Subsystems: Data Store • Includes retrieval and storage of raw science data, but also “much more”. • Captures “everything” (e.g. raw FSI data, reduced data, OBS plans, instrument modes, pipeline parameters, science personnel). • Enables easy import & export in variety of formats (e.g. general investigators, IPAC) by being platform neutral. SOFIA Data Cycle System: Overview

  20. DCS Subsystems: Data Store Obtain OBS plan, store raw FSI data DCS Storage Data Acquisition User profile User Interaction Layer Storage access is unique to task’s needs Obtain raw FSI data, store reduced data Task Library Data Reduction SOFIA Data Cycle System: Overview

  21. DCS Subsystems: Data Acquisition • Data acquisition, like the rest of the DCS, is composed of small modules working in concert together. • Modularity insulates the DCS from instrument specifics, and encourages re-use between similar instruments. • Effectively, the DCS “translates” an experiment to instrument specific commands and needs. SOFIA Data Cycle System: Overview

  22. DCS Subsystems: Data Acquisition Obtain OBS plan, store raw FSI data DCS Storage Data Acquisition User Interaction Layer Initiate, monitor, and control data acquisition quick look Task Library Data Reduction SOFIA Data Cycle System: Overview

  23. DCS Subsystems: Data Reduction • Instrument science teams focus on algorithm development, not the DCS. • Reduction is automatic, distributed, pipelined, and relentless. • DCS Data Reduction removes the need for every GI to have their own compute engines, but does not prevent GI from doing their own reduction. SOFIA Data Cycle System: Overview

  24. DCS Subsystems: Data Reduction DCS Storage Data Acquisition User Interaction Layer Obtain raw FSI data, store reduced data Task Library Data Reduction Initiate and monitor data reduction SOFIA Data Cycle System: Overview

  25. DCS Subsystems DCS Storage Data Acquisition User Interaction Layer Task Library Data Reduction SOFIA Data Cycle System: Overview

  26. DCS Technologies Built on top of the COTS technologies CORBA and XML, the DCS team is developing four new technologies that enable the overall DCS: • DCS Registry • Data Typing • Data Connection Association Object (DCAO) • XML Parser Generator SOFIA Data Cycle System: Overview

  27. DCS Technologies: DCS Registry • Enables various modules in the DCS to locate each other based on combinations of names, versions, and other criteria. • Allows simultaneous, non-interfering deployment of modules with the same functionality: • Modules that are proven and trusted • Modules undergoing evaluation and test SOFIA Data Cycle System: Overview

  28. DCS Technologies: Data Typing • Provides a “live” dictionary for use in the DCS that defines various data types and formats. • Best explained by example: data typing allows objects to interact with each other using “rawFrameAIRES” instead of “IEEEsingle[1024][1024]”. • More expressive than IDL; addresses more portability and platform issues. SOFIA Data Cycle System: Overview

  29. DCS Technologies: DCAO • Provides common language, interface, and linkages between groups of objects that must locate and communicate with each other at runtime. • Directly enables the Data Acquisition and Data Reduction subsystems, both of which rely heavily on dynamic collections of objects. SOFIA Data Cycle System: Overview

  30. DCS Technologies: Parser Generator • Extends existing event-driven XML parser (expat) by generating the support code normally written by engineers to use a particular DTD. • “Software writing software”, that ultimately yields a parsed DOM-like object for any given combination of XML document and DTD. SOFIA Data Cycle System: Overview

  31. Subsystems User Interaction Task Layer Data Store Data Acquisition Data Reduction Technologies Registry Data Typing DCAO XML Parser Generator DCS Rundown SOFIA Data Cycle System: Overview

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