Communications of the ACM

The factors underlying system design for usability are examined and the role and responsibilities of a usability committee described. Under the control of a usability committee, a balance between high levels of system function and usability was reached ...

Mxec is a sophisticated computing environment (executive system) which extends and magnifies users' interactions with a computer. Principally, Mxec provides for parallel processing and also assumes many of the mundane, clerical tasks with which users of ...

This paper presents a framework for describing users' knowledge of how a simple four-function calculator operates. Differences among novices and experts in their conceptions of “what goes on inside the calculator” for various sequences of button presses ...

The steady increase in the power and complexity of modern computer systems has encouraged the implementation of automatic file migration systems which move files dynamically between mass storage devices and disk in response to user reference patterns. ...

The distribution of keys in a computer network using single key or public key encryption is discussed. We consider the possibility that communication keys may be compromised, and show that key distribution protocols with timestamps prevent replays of ...