Discusses reasons for the development of an online catalog using computer output microfiche (COM) supplements to the card catalog in a university library, and outlines some of the principles used in designing the online system. Three references are cited. (CHC)

Describes two experiments that were conducted at the University of Illinois to determine how cognitive abilities of users of information retrieval systems and specific design features combine to create system usability. Logical reasoning and perceptual speed are examined, and reliability and validity are discussed. (Contains 12 references.) (LRW)