NSSDC Archiving Milestones Passed

By Joe King

NSSDC has been creating a new nearline permanent archive based on DLT jukebox technology, the CCSDS/ISO Open Archive Information System standard and a homebuilt software environment ("DIOnAS"). For external user access, this software also populates a magnetic disk farm with most of the DLT-targetted data. The software builds a database ("the DIOnAS database") about these data.

NSSDC has now reached just over 1 terabyte of data on the jukebox and just over 1 million files ftp-accessible from magnetic disk and known to the DIOnAS database. Most of these data had been on NDADS, NSSDC's now-retired optical disk jukebox. In addition, data currently arriving at NSSDC are typically ingested to DIOnAS as they arrive.

Known to the DIOnAS database are data from eight space physics programs (DE, IMAGE, IMP, ISEE, ISIS, SAMPEX, Voyager and Wind) and from one astrophysics mission (IRAS). By byte count in the jukebox, dominant missions are ISIS, DE, IMAGE, IRAS and SAMPEX. By magnetic disk file count, dominant missions are ISIS, IRAS, DE and IMP 8.

Additional data that are network-accessible to customers but not yet ingested to this new archive are CDAWeb holdings, other data on magnetic disk, etc. NSSDC's primary site for ftp-accessible data involves DIOnAS-ingested data and not-yet-DIOnAS-ingested data in interspersed directories.

This new archiving approach, including the DIOnAS system and related software and the OAIS standard were described in the December, 2000, issue of this newsletter.