Abstract: A method is used in managing data storage in virtual systems. A data storage system is queried through a universal framework module of the data storage system. The universal framework module includes a first set of interfaces associated with a format used by a virtual system to communicate with the data storage system. Information associated with the data storage is retrieved from a platform specific module of the data storage system. The platform specific module provides the information to the universal framework module. The platform specific module includes a second set of interfaces based on a type of the data storage system.

Abstract: A method is used in sizing volatile memory (VM) cache based on flash-based cache usage. A user selection for a flash-based cache is received. Based on the selection, configuration and sizing factors are provided, by a flash based cache driver, to VM cache size determination logic. Based on the configuration and sizing factors and a sizing formula and rules, a requested VM cache size is produced by the VM cache size determination logic. Based on the requested VM cache size, the VM cache is caused, via VM cache resizing logic, to be resized to the requested VM cache size.

Abstract: A method is used in managing caches for reporting storage system information. A cache is created. The cache includes information associated with a set of storage objects of a data storage system. The information of the cache is made available to a virtual system. The virtual system uses the information for reporting storage system information. The virtual system is notified for retrieving updated storage system information from the cache.

Abstract: Described are techniques for reporting requested information to a client. A bidirectional graph is stored in a cache. The bidirectional graph includes a first set of nodes and a second set of edges between pairs of nodes of the first set, each node of the first set representing an object in an object model of a server. Each edge of the second set between a pair of nodes of the first set represents an association between two objects corresponding to the pair of nodes. A request is received from the client. A response to the request is determined by traversing a portion of the bidirectional graph to extract first information, and filtering the first information in accordance with a usage context customized for the client.

Abstract: A dual beam hydrophone wherein a reference laser beam and a signal laser m are both modulated simultaneosuly by the movement of reflecting surfaces responding to pressure variatrions due to an impinging acoustic wave. Each beam, travels the same path length within the hydrophone before being detected, thus eliminating any otherwise needed signal compensation. The reference beam and signal beam are acoustically modulated 180 degrees out of phase which reduces by one half the number of reflections normally required to produce the same sensitivity.

Abstract: A system for signal stabilizing in-phase modulated optical hydrophone arr employs interferometry with homodyne detection. Phase stabilization is accomplished by modulating the input laser signal in proportion to variations in the output of an optical transducer to balance the output phase so that the fringes are kept at optimum position. Additionally, fluctuations in light intensity are compensated for so that a photodetector responds only to phase shift variations. The technique used is to split the input beam into signal and reference beams using a beam divider, exposing the signal beam to the acoustic pressure of interest, recombining the signal beam with the reference beam, detecting the combined beams and filtering the resulting signal to separate out the acoustic information of interest from the phase shift and light intensity portions used to stabilize the input beam.

Abstract: Optical sensing devices comprising dual chamber apparatii which use signal and reference light beams together with interferometric methods for detection of physical quantities of interest. The signal part of the chamber experiences the effects of a particular physical quantity to be measured which produces variations in the optical length of the light beam by movement of a mirror, thereby modulating that beam in proportion thereto. Concurrently, the reference beam, of equal pathlength, is passed through an adjacent chamber, isolated from such effects. The modulated signal beam and unmodulated reference beam are then combined to form a fringe pattern, the zero and first order fringes which are superimposed on apertures of an optical fibers, which carry the resultant light beams to a photodetectors for converting the optical signals to proportional electrical signals.

Abstract: A wide-area acousto-optic hydrophone which uses signal and reference laser beams together with interferometric methods for detecting underwater acoustic signals. The signal beam is distributed across the wide sensing area of the hydrophone using beam folding techniques while being directly transmitted through a sensing chamber filled with an optically transparent bulk material, the refractive index of which varies with the incident acoustic pressure thereby modulating the signal beam. Concurrently, a reference beam of equal length and folded in an identical pattern is directly passed through an adjacent chamber filled with the same bulk material. A microhole joins the two chambers, to expose the reference beam to the same static pressure and temperature fluctuations as the signal beam thus serving as a low pass filter.

Abstract: An acousto-optical transducer which includes a pair of mirrors of high reflectivity arranged in parallel to form an etalon. A laser beam enters the etalon at a small angle of incidence through a window and after suffering many reflections at the etalon mirrors exits at the second window. The reflected beam carries the information imposed by an acoustic pressure wave which affects the position of the etalon mirrors. The reflected laser beam of changed frequency due to the doppler shift caused by the motion of the etalon mirrors relative to the source of the incident laser beam is then used to beat with a light of a fixed frequency by using the heterodyne technique. Alternatively, an additional mirror is used which is generally perpendicular to the etalon mirrors and facilitates the reflections at the etalon mirrors for the ultimately reflected beam.

Abstract: A fiber-optic acoustic array using optic hydrophones wherein sound waves are sensed and displayed as modulated light signals. The light signals so generated are transmitted along the fiber-optic bundles. Many such hydrophones are arranged to form acoustic arrays of increased sensitivity and directionality.