Abstract: A data network includes a switch that links a number of host processors to shared resources such as network ports of a cached storage subsystem. The switch routes resource requests from its inputs to selected ones of its outputs in accordance with programmed routing information. The routing information is changed dynamically based on measured loading characteristics of requests from the switch inputs or the respective hosts, in order to reduce the probability of blocked paths. In a specific example, respective subsets of output ports of the switch are assigned to each respective input port, the loading of each input port of the switch is measured, and the respective subset of output ports assigned to each input port are repetitively changed, and the respective subset of an input port is changed in response to blocking of the output ports assigned to the input port.

Abstract: A method and apparatus for managing blocks of information in a disc drive storage system. One embodiment is directed to a disc drive storage system that employs a plurality of disc drives, and that mirrors blocks of information on different physical locations within at least two of the disc drives. Preference may be given in each of the mirrors to reading blocks of information that are closer to an outer edge of the disc to improve system performance. Another embodiment is directed to the handling of a hot spot by reading blocks of information within the hot spot from a mirror in the system that is not read during normal operation. A further embodiment addresses hot spots by temporarily employing another disc drive as a temporary mirror to enable parallel access to blocks of information within the hot spot.

Abstract: A method of managing information to be stored on a storage disc in a disc drive system to achieve improved system performance. Some of the data on the disc may be mirrored on the same surface of the disc to reduce latency and/or seek time. Compression techniques may be employed to limit reductions in the storage capacity of the disc. In another embodiment, data is preferentially stored on the outer tracks of the disc because system performance is greater when accessing outer tracks. Compression techniques may also be employed with this embodiment to limit reductions in the storage capacity of the disc. Compressed data stored on the disc may be transferred to another storage medium in its raw compressed form to reduce the number of instructions that would be required to transfer the data if it were decompressed before transfer.

Abstract: A method and apparatus for managing blocks of information in a disc drive storage system. One embodiment is directed to a disc drive storage system that employs a plurality of disc drives, and that mirrors blocks of information on different physical locations within at least two of the disc drives. Another embodiment is directed to the handling of a hot spot by temporarily employing another disc drive as a temporary mirror to enable parallel access to blocks of information within the hot spot.

Abstract: A method of managing information to be stored on a storage disc in a disc drive system to achieve improved system performance. Some of the data on the disc may be mirrored on the same surface of the disc to reduce latency and/or seek time. Compression techniques may be employed to limit reductions in the storage capacity of the disc. In another embodiment, data is preferentially stored on the outer tracks of the disc because system performance is greater when accessing outer tracks. Compression techniques may also be employed with this embodiment to limit reductions in the storage capacity of the disc. Compressed data stored on the disc may be transferred to another storage medium in its raw compressed form to reduce the number of instructions that would be required to transfer the data if it were decompressed before transfer.

Abstract: A method and apparatus for managing blocks of information in a disc drive storage system. One embodiment is directed to a disc drive storage system that employs a plurality of disc drives, and that mirrors blocks of information on different physical locations within at least two of the disc drives. Preference may be given in each of the mirrors to reading blocks of information that are closer to an outer edge of the disc to improve system performance. Another embodiment is directed to the handling of a hot spot by reading blocks of information within the hot spot from a mirror in the system that is not read during normal operation. A further embodiment addresses hot spots by temporarily employing another disc drive as a temporary mirror to enable parallel access to blocks of information within the hot spot.

Abstract: A method of managing information to be stored on a storage disc in a disc drive system to achieve improved system performance. Some of the data on the disc may be mirrored on the same surface of the disc to reduce latency and/or seek time. Compression techniques may be employed to limit reductions in the storage capacity of the disc. In another embodiment, data is preferentially stored on the outer tracks of the disc because system performance is greater when accessing outer tracks. Compression techniques may also be employed with this embodiment to limit reductions in the storage capacity of the disc. Compressed data stored on the disc may be transferred to another storage medium in its raw compressed form to reduce the number of instructions that would be required to transfer the data if it were decompressed before transfer.

Abstract: A computer having capabilities for hierarchical storage of data, said computer including an interpreter that maps logical user read and write requests to physical block level read and write requests, and a hierarchical performance driver having a disk driver interface for receiving the block level read and write requests from the interpreter, the hierarchical performance driver issuing instructions to read and write data from plural data storage devices in response to block level read and write requests, plural data storage devices having different data access speeds, the hierarchical performance driver monitoring the rates of access of blocks of data stored on the data storage devices and transferring blocks of data accessed infrequently from a faster data storage device to a slower data storage device.

Abstract: A host computer including an interpreter that maps logical user write requests to physical block level write requests, a host storage driver having a disk driver interface for receiving block level write requests, a host storage disk connected to be controlled by disk control signals of the host storage driver, and a redundant disk system having a disk driver interface to the interpreter and a remote procedure call interface to one or more associated computers connected to the host computer over a network, the redundant disk system sending write requests and data to be written from the interpreter to the host storage driver and to at least one of the other computers connected to the network.

Abstract: A method of managing information to be stored on a storage disc in a disc drive system to achieve improved system performance. In one embodiment, data is preferentially stored on the outer tracks of the disc because system performance is greater when accessing outer tracks. Compression techniques may be employed with this embodiment to limit reductions in the storage capacity of the disc. The compression ratio can have any value, including compression ratios less than 2:1, or of F:1, wherein F is a non-integer. In another embodiment, a storage system is provided having sectors of different sizes. The different sized sectors may be on the same disc surface, on different disc surfaces, or on different disc drives. The differently sized sectors can be used to store blocks of information having different sizes to minimize the number of sectors read, thereby improving system performance.

Abstract: A method of sending a plurality of commands to a remote device which executes the plurality of commands, the method including the steps of encapsulating the plurality of commands within a single command; and sending the single command to the remote device.

Abstract: A computer having restore capabilities for data backed up on archive media, the computer including a restore application which identifies the target data to be restored from the archive media and makes logical user read and write requests, an interpreter that does logical to physical mapping and maps logical user read and write requests to physical block level read and write requests, a host storage driver having a disk driver interface for receiving block level read and write requests from the interpreter, a host storage disk connected to be controlled by the host storage driver, and a restore system having a disk driver interface to the interpreter for receiving block level read requests from the interpreter, the restore system issuing instructions to read data from archive media at a block, physical level and returning the data obtained from the archive media to the interpreter.

Abstract: A method of prefetching data within a data storage system that includes at least two levels of data storage including a first level and a second level and that also includes an intelligent controller that interprets and executes received commands from a host processor connected to the data storage system, the method including the steps of receiving a prefetch command that identifies a list of data blocks within the first level of data storage; and prefetching from the first level of data storage into the second level of data storage all of the data blocks identified in the list.

Abstract: A computer having backup capabilities for backing up data on a host storage disk of the computer to a remote archive repository, the computer including a backup application that determines when data to be backed up should be copied to the remote archive repository and makes read requests to make a copy of data on the host storage disk and makes write requests to store the copy at the remote archive repository, the computer also including a backup system that receives the write requests and the copy of data and has a remote procedure call interface for transmitting the data to the remote archive repository.

Abstract: A method for testing for short circuits between UUT pins that are nominally connected to nodes on a circuit board which the UUT is mounted and open circuits between pins and nodes nominally connected thereto. The method is used in a system that responds to the capacitances between a plate positioned above the UUT and respective nodes to which the pins are connected. A group of pins are selected such that no two pins of the group are nominally connected together. The pins are connected together in the tester and if the capacitance between the plate and the pin group is less than a first threshold an open circuit is indicated. The presence of a short circuit is indicated by a capacitance greater than a second threshold that is greater than the first threshold.

Abstract: A system for generating programs for a variety of testing stations. A program generator reads a common rule set to generate test instructions for an electrical tester, an optical inspector, and an x-ray inspector. Over time, the system collects defect data that may affect the triggering of certain rules in the rule set.

Abstract: A connector, for use with an automatic test system for testing integrated circuit boards, consists of a non-conductive carrier that supports a plurality of electrically conductive contacts. In a preferred embodiment, the carrier includes a plurality of holes, each of which is filled with a wire mesh. The wire mesh compresses as necessary to accommodate variations in the lengths of the leads of the device-under-test or the wires of a system component, such as the system fixture. In an alternative embodiment, a flexible carrier supports a plurality of wires. The wires may be embedded in the carrier, or they may be wrapped partially around the carrier, to electrically connect leads proximate to top of the carrier with leads or contacts proximate to the bottom of the carrier. In a second alternative embodiment, the connector consists of a plurality of conductive drops, that are strategically placed on the ends of wires, leads or contacts.

Abstract: A probe fixture for an automatic circuit board tester has a high density array of probe pads. The array of probe pads are sized and spaced apart to ensure contact with all of the test points on the device under test (DUT). The width of the pads is made smaller than the known minimum separation of the test points, and the separation of the pads is made smaller than the known width of the test points. The pads are connected to remote contacts of the fixture. A multiplexer unit may be provided to connect the desired test circuits to different probe pads of the fixture. Using the multiplexer unit, a controller of the tester can individually test the relative connection status of each of the probes of the fixture. By comparing to the known test point layout of the DUT, the controller then determines which of the probe pads is in contact with which of the test points and proceeds with the desired test functions accordingly.

Abstract: In a fixture (24) are mounted a plurality of probes (28) so disposed as to enable them simultaneously to contact test points on a circuit board (26) to be subjected to an in-circuit test. Wiring (30) connects the probes (28) to respective fixture pins (22) that mate with the system pins (20) by which a general-purpose tester (12) provides connections to various test instruments (14). The wiring (20) is so provided that certain of the probes (28) are wired together and thus require fewer system pins (20) than there are probes (28).

Abstract: In a method for testing whether a pin (12) of an electronic component (14) on a circuit board under test (18) has been properly connected to a circuit-board track (16), a source (20) drives the track (16), and a capacitive probe (34) located above the component (14) generates a resultant output. The pin (12) is determined to be connected correctly if that output exceeds a threshold determined for that pin (12) during a training process in which similar measurements have been made on a known good board for that pin and other pins on the same electronic device. The threshold is determined by dividing the capacitance measurement made during the training process for that pin into connection-dependent and connection-independent parts, the latter being the part that would result even in the absence of a proper pin connection.