Volume 16, Number 2, June 2000
By Edwin Bell
NSSDC has recently made a number of changes to two key metadata data bases as a part of an effort to provide improved services for NSSDC customers. These data bases, accessed by the public through the NSSDC Master Catalog (NMC) and Personnel Information Management System (PIMS) interfaces, have been upgraded to Oracle 8i, merged, and moved to a machine dedicated to the data base engine. In addition, NSSDC has moved the interfaces used by internal staff to populate these data bases off the main NSSDC Web server to a separate dedicated machine to reduce further the load on the Web server and has replaced the cgi-bin programs with Java servlets.
The most visible changes to NSSDC's customers will be in the appearance of some of the pages displayed via the NMC interface. When accessing the spacecraft query page ( http://nssdc.gsfc.nasa.gov/nmc/sc-query.html), the results page now displays all of the spacecraft (up to the limiting number) that satisfy the search criteria. The tabular format for this (and other "hits" lists throughout NSSDC interfaces) is now consistent with that used in the PIMS interface since October 1999. The display pages for spacecraft, experiments, and data sets are relatively unchanged, the differences mainly attributable to corresponding alterations in NSSDC's data base. An example is NSSDC's recent use of the full International Launch ID for designating spacecraft whereas before NSSDC has used a truncated version (minus the century designation 19 or 20).
While staff expect these changes to improve the performance of the Web server, a number of additional changes were made to the NMC data base for other reasons. These changes were made to allow for future work, including easier searching of information, better extensibility, and integration with NSSDC data files, data volumes, and image inventories. Some of these changes should become more evident as staff continue to make other changes (for example, to NSSDC's data inventory data bases) to enable better access to NSSDC information and data. User feedback on the effectiveness of these changes in promoting ease of use of NSSDC data bases is most welcome.
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Author: Miranda Beall