This paper is primarily an annotated listing of criteria for selection of a microcomputer to be used for online information retrieval. The paper was used by the University Library of the Technische Universitat Wien (Vienna, Austria) while preparing to contact computer dealers and to inform them about the library's needs in this specialized area of operation. The paper has two parts: a short list of system requirements and an extensive description of criteria and necessary features. Compatibility with the Plot 10 graphics of Tektronix is emphasized because the computer is to be used in part for searching the chemical structure systems (DARC, CAS ONLINE). The requirements for a printer and an external mass storage medium (floppy disk, Winchester hard disk) are also discussed. Considerations concerning software and telecommunications are included. (Author/THC)