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Baker and Eick [1] created a tool to aid in the management of extremely large, multi-million line programs. The only practical way to display programs as large as this is with the use of statistics. Their program, SeeSys, works at the file, directory and subsystem level. It displays information about a program by subdividing the screen into rectangles, representing the subsystems of the program. The size of each rectangle represents the size of the subsystem, measured in non-commentary source lines (NCSL). Each rectangle is then similarly subdivided into directories. The user can focus on a particular region and have it expanded to show detail, for example a directory could be expanded to show the sizes of the files within it.
The system provides five different statistical views on the program. These are:
The most useful aspect of the system is that it allows the user to quickly browse through a very large program focusing in on details that are of interest. This is because of the hierarchical structure of the information presented, which allows the user to go from any position in the code to any other in only a few operations. However, for this technique to be successful, the hierarchy needs to be organised in a logical way, so that the user has a clear idea of which box to click on next to get to the next area of interest. The authors make note of the usefulness of spatial relationships between objects in providing this logical structure. Human beings naturally make inferences from the way objects are positioned in relation to each other, and this speeds up their processing of information.