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Paper: Data Access Layer to Support Variable Inputs Using C
Volume: 216, Astronomical Data Analysis Software and Systems IX
Page: 563
Authors: Cresitello-Dittmar, M.
Abstract: This paper provides an overview of a software library developed at the Chandra X-Ray Observatory Science Center (CXC) to accommodate variability in the input data products to the aspect determination system. The issue arose that, depending on the decommutation templates used, the inputs to these tools would vary. This variation could be in the number of files, the columns contained in each file, and the form (type) of the column. We needed a layer of software that would dissociate a data column (element) from any particular file. It would also need to handle timing variations for inputs provided at different sample rates. The software described in this paper is a library of functions and structures written in C, that define and manipulate data elements. Tools using this library provide a set of input files containing the required elements. The library functions sort the input files by type, locate the required elements in those files and provide access to them in a time-correlated fashion. The design of the system also makes it easy to define and create new data products.
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