Volume 14, Issue 4, December 1998
NSSDC has over the years provided FTP-based network access to many data sets and others services. Initially, this service was provided from the VMS environment (computer NSSDCA) and over recent years also from the UNIX environment (computer NSSDC). Most but not all anonymous directories originally created on NSSDCA have been moved to or mirrored at NSSDC. Many directories now exist solely on NSSDC.
Further, there was little central control of what anonymous directories were created by various staffers and placed on either machine, and what the naming of these directories would be. The result was that it became unclear to NSSDC's customers where to look for which FTP-accessible data or services and sometimes how to recognize the right directories because of the use of non-informative directory names.
To rectify this situation, NSSDC has undertaken to cast the UNIX anonymous environment as the definitive environment and to regroup and rename many of the anonymous directories and subdirectories there. For instance, this anonymous area will be linked to from the higher level Web pages. There will remain an anonymous area in the VMS environment only for those directories, subdirectories, and files specifically needing VMS support.
These VMS-resident directories will be pointed to from logical places in the definitive UNIX anonymous environment.
While NSSDC would aim to have a set of top level UNIX anonymous directoriesthat provided brevity and easy user comprehensibility (on executing a "list" command or on reaching the directory listing from a WWW page), staff will also maximally preserve present directories that are significantly used.
While not finalized at the time of this writing, the expectation for the top level
directories is as follows. Those directories marked with an asterisk are being retained
unchanged from their pre-reorganization state owing to the high access frequencies to
these directories.
| ccsds * | Consultative Committee for Space Data Systems documents at various stages of review |
|---|---|
| cdrom * | Contains selected images from NSSDC's CD-ROM collection |
| data_by_topic * | Multisource collections of data associated with given science topic or theme |
| data_dist * | Staging area for data files promoted from off-line holdings or created dynamically by WWW-based systems |
| data_fmt_stds * | Material related to CDF, FITS, and SFDU format standards |
| miscellaneous * | Material not closely linked to any of the other directories |
| models * | Numerous geophysical models: coefficients and code |
| orbits * | Mostly spacecraft launch and trajectory information; formerly called "active" |
| photo_gallery * | Array of planetary and other images and captions |
| planetary * | Planetary images documents too large or inappropriate for WWW site |
| software * | Software, including pointers to software associated at and included with other anon directories |
| spacecraft_data * | Spacecraft data being made anon/ftp-accessible by NSSDC, organized by spacecraft name |
Note especially the spacecraft_data directory for science data held permanently on line for FTP access that complements the much larger data volume held on NDADS's near-line mass storage for access through such NASA Data Archive and Distribution Service (NDADS) interfaces as The Space Physics Catalog (SPyCAT), The Web Interface for Searching Archived Research Data (WISARD), and Automated Retrieved Mail System(ARMS). Staff expect that in the future, the NDADS (MSS) environment will include a large magnetic disk component and that the data on these disks will be available by either FTP or through the NDADS interfaces.
Note also that there will be appropriate cross-pointing between and among directories,
as for example between the data_by_topic directory and the spacecraft_data directories.
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