Construction of the Data Server

The data server structure is shown in Figure . The `data server' is actually a collection of three separate programs which correspond to the three data objects in the DAP. There is no coordination of effort between the three programs; each operates independently⁶.

Each of the three programs which comprise the data server use the Common Gateway Interface mechanism to receive parameters from HTTPD (which is used to invoke the programs and manage the network I/O connections--see Figure ). Once parameters have been parsed, the programs read information from the data set which is used to satisfy the query. Accesses to the data set are made using an established API. Thus each of the programs consists of two modules:q CGI interface and a data-access API. The paper ``DODS--Client and Server Toolkit'' contains information on software which is designed to aid in the construction of these parts of the data server software.