Abstract: An amplifier particularly suited for use as a sense amplifier for the detection of magnetic bubble domains in a magnetic bubble chip. A feedback loop is used to reduce D.C. offset of the input and output signals. Noise unavoidably introduced into the feedback loop is cancelled upon input of the feedback signal into the amplifier. The noise cancellation is effected by the introduction into the amplifier input of another noise signal of equal magnitude and opposite polarity provided by another noise pickup loop separate from the feedback loop.

Abstract: A method for selecting data storage media for demount in an automated storage library, and an automated storage library and program product therefor are disclosed. Preemptive demount of storage media is permitted when all peripheral storage devices in the library are occupied and one or more of such devices remains inactive for a predetermined time. Storage media may be demounted to service existing mount requests, provided the peripheral storage devices in which the media are mounted are inactive. There is also a need, however, to ensure the availability of an empty device to service future mount requests, particularly in libraries having only a single gripper mechanism. Thus, even when no mount requests are pending, the status of the peripheral storage devices is continually monitored.