Introduction.md is an overview of NIDAS written by the original author, Gordon Maclean.
Recent changes are noted in the Changelog.
See BUILDING.md for notes on building and developing NIDAS.
See PACKAGES.md for installing NIDAS from RPM or Debian packages.
The EOL web site hosts the NIDAS API documentation generated with Doxygen, but it is not always updated.
See timetags.md for a disucssion of time tags in NIDAS.
NIDAS needs more documentation and a clear plan for hosting it. Currently most (and certainly the most current) documentation is in markdown files within the source repository, some of it having been migrated from the wiki and google docs.
One possibility is to use a second github repository to host a static web site, generated from the NIDAS source, so it includes both the markdown pages and the Doxygen API documentation. Keep the generated documentation and rendering artifacts out of the source repository, while the information can still reside with the source.
In particular, NIDAS is lacking documentation on the XML configuration, since that is a fundamental part of the data acquisition, but it has many esoteric settings and variations.