Abstract: An apparatus for storing and monitoring a plurality of articles, including at least one cabinet or carrier having a plurality of receptacles in which the articles are stored. In one application, the apparatus is utilized to maintain a library of magnetic tapes or other storage media associated with a data processing center. Each of the articles is identified by a respective code or volser number, and requests for the articles are received by the system in the form of requests for a particular volser number. In a preferred embodiment, the articles may be randomly stored in any of the receptacles in any of a plurality of carriers. The system includes a polling and searching system operable to identify the carrier in which a requested article is currently stored, and a display system operable to display the carrier's location. A host computer controls the operation of the system, but no central data base is maintained of the coded articles.

Abstract: An apparatus for testing respective electrical components in situ within a circuit having a plurality of the electrical components. A power bus is connected between a power source and switching devices operable for conducting test current to respective ones of the electrical components. A comparator circuit includes inputs connected to the power bus and to a reference potential. A processor is programmed to actuate respective switching devices for causing a test current to be conducted from the power bus through a respective component, while sensing any output signal from the comparator circuit corresponding to an increased potential on the power bus indicative of a reduced current flow caused by an open or failed component.