During the last few months NSSDC has been copying data currently stored on Optimem 12" Write Once Read Many (WORM) optical disks to Digital Linear Tape (DLT). This migrating of data to a more modern medium is required by the imminent obsolescence of the Optimem drives.
The data currently being moved to DLT consist of approximately 60 platters of Dynamics Explorer (DE) and International Sun-Earth Explorer (ISEE) data. These platters are being copied on NSSDC's Media Replication System (MRS). The DLT files are labeled so as to point back to the original Optimem platter from which the data were copied. This information is entered into one of NSSDC's data bases. The data on the 60 2-GB platters will all reside, uncompressed, on nine DLT tapes.
Currently, two other groups of platters are being reviewed for possible inclusion into this migration effort. These groups contain a few hundred platters holding DE telemetry data owned by the DE Project and approximately 50 platters holding data from the 1980s Solar Maximum Mission (SMM) spacecraft. Other groups believed to have Optimem drives who are regular data providers to the data center have been surveyed as to their having any additional data to submit. NSSDC expects to receive no further data on this medium.
A chapter in NASA's data management history that began with a 1986 NSSDC-orchestrated, community-involved mass buy of Optimem optical disk drives is quietly ending.
Erin D. Gardner, email@example.com, (301) 286-0163
Hughes STX, Code 633, NASA Goddard Space Flight Center
Greenbelt, MD 20771, U.S.A.