User Behavior on an Interactive Computer System

behavior are discussed that concern the duration and frequency of terminal sessions, the use of language processors, user response time, and command usage. The methodologies of the behavioral sciences can provide data useful to systems engineers and designers of complex information processing systems. For example, the quantitative description of the usage of existing systems can provide an understanding of those features that should be retained, deleted, or modified as new systems evolve. This paper summarizes one aspect of an ongoing project at the IBM T. J. Watson Research Center. The project has as its goal a basic understanding of the behavioral factors that limit and determine human performance in interactive computer systems. Reported here is an observational analysis of user interaction with a complex interactive system, the IBM System/360 Time Sharing System (T S S / ~ ~ O). ~ ' ~ The paper is divided into two sections. The first provides a brief description of TSS/360 and the method used in this study. The balance af the paper reviews our results relative to user behavior. Among the issues discussed are the following: the duration and frequency of terminal sessions; the use of language processors; command usage; and user response time and its determinants.