FreeForm ND uses a format descriptor file to describe the format of one or more data files. This descriptor file is a simple text file that can be created with a text editor, describing the structure of your data files.
A traditional DAP2 server, illustrated in figure 1.1, receives a request for data from a DAP2 client who may be at some remote computer2. The data served by this server must be stored in one of the data formats supported by the OPeNDAP server (such as netCDF, HDF, or JGOFS), and the server uses specialized software to read this data from disk.
When it receives a request, the server reads the requested data from its archive, reformats the data into the DAP2 transmission format and sends the data back to the client.
The OPeNDAP FreeForm ND Data Handler works in a similar fashion to a traditional DAP2 server, but before the server reads the data from the archive, it first reads the data format descriptor to determine how it should read the data. Only after it has absorbed the details of the data storage format does it attempt to read the data, pack it into the transmission format and send it on its way back to the client.
