Reproduced, with permission, from:
National Aeronautics and Space Administration. 1993. Master Directory User's Guide, ed. J. Shipe. Greenbelt, MD: National Aeronautics and Space Administration Goddard Space Flight Center.
Alphanumeric Interface
Version 2.0
April, 1993
Prepared by Janis Shipe, Hughes/STX
for
NASA Goddard Space Flight Center
The Master Directory (MD)
The Master Directory (MD) is a free, on-line multidisciplinary database of information about data holdings of potential interest to the scientific research community. The MD contains high level descriptions of data set holdings of various agencies and institutions. It also contains supplementary descriptions about these data centers, as well as scientific campaigns and projects, sources (spacecraft, platforms), and sensors (instruments).
The holdings described in the Master Directory focus on the Earth and space sciences. Future data set descriptions will include microgravity and life sciences disciplines. The MD does not contain the actual data sets themselves, but serves as a pointer to them, functioning much like a telephone directory. Users should be able to obtain enough information about a data set from the MD to determine if they want to obtain further information at the data center holding the data set. In essence, the directory should be used as a first step for researchers in finding data sets of potential interest or use in their research.
Because the intent of the MD is to direct users to data sets of possible interest, it describes a wide variety of data sets. Consequently, uniformity across all descriptions is loosely defined. For example, one directory entry may point to a small, unique data set, where another entry may point to an aggregation of a number of many similar data sets. In addition, the information from which the directory entries are constructed also varies, so some entries are more expansive than others. Every entry, however, contains information about a person or institution to contact for more information about the data set.
The MD also provides automatic connections called LINKs to many of the data centers or data systems holding the data sets. These connections are available from a simple command which can be activated from several places in the directory. LINKs represent the first major step in the Catalog Interoperability Project (CI), whose objective is to enable researchers to quickly and efficiently identify, obtain information about, and access data.