A software design document is a written description of a software product, that a software designer writes in order to give a software development team an overall guidance of the architecture of the software project. A software design document usually accompanies an architecture diagram with pointers to detailed feature specifications of smaller pieces of the design. A design document needs to be a stable reference, outlining all parts of the software and how they will work. The document is commanded to give a fairly complete description, while maintaining a high-level view of the software.
The following Design Documents are available here for GMAT:
The architecture design uses information flowing characteristics, and maps them into the program structure. The transformation mapping method is applied to exhibit distinct boundaries between incoming and outgoing data. The data flow diagrams allocate control input, processing and output along three separate modules.
Interface Specs (Old Wiki: System QA Tracking)
The interface design describes internal and external program interfaces, as well as the design of human interface. Internal and external interface designs are based on the information obtained from the analysis model.