The UCSD MSG System: Iterative Design in the UNIX Environment

This paper is an investigation into the process of design of a user interface. The starting point was a fully implemented electronic mail software package called the “MSG System”. The design technique employed is an iterative one— feedback from a community of test users shaped each successive version of the software. This iterative design technique has produced a user interface preferred by many users of the original version. The design process is discussed, along with some of the more important features that were developed. The technique with which the introductory user manual was structured is described. Limitations of the iterative design technique and implications for a principled design are also discussed.