International Business Machines Corporation

Robert Frank Maddock

Robert Bruce Nicholson

Paul Nicholas Cashman

Reginald Beer

Paul Hooton

Ian David Judd

Neil Morris

Barry Douglas Whyte

Paul Jonathan Quelch

Michael Alan Veal

Barry Douglas White

Carlos Francisco Fuente

Henry Esmond Butterworth

A method and apparatus for relating a device name to a physical location of a device () on a network is provided. The network may be a serial loop network, for example a Fibre Channel Arbitrated Loop network. The network includes a plurality of devices () on or connected to the network () and a control device () with control over at least one of the devices (). Each device () has a check output () independent of the network () with connection means () to a control device (). The method includes the step of sending a device name from the check output () of a device () to the control device (). The check output () of a device () is also connected to an external indication means for indicating the failure of the device ().

Method and apparatus for relating device name to physical location of device on a network

A method and apparatus for recovery from faults in a loop network () is provided. The loop network () has a plurality of ports () serially connected with means for bypassing the ports () from the loop network (). A control device () is provided with bypass control over at least one of the ports (). A host means () sends a command to the control device () at regular intervals and the control device () has a counter which restarts a time period at the receipt of each command. If the time period expires, the control device () activates the means for bypassing all the ports () under its control. The loop network () may have two loops () with at least some of the ports () common to both loops ().

Method and apparatus for recovery from faults in a loop network

Provided are RAID storage systems, methods, and controllers for RAID storage systems. A first method includes storing a first copy of the data in a first RAID array corresponding to a first RAID level providing redundancy (such as RAID-5), and storing a second copy of the data in a second RAID array corresponding to a second RAID level (such as RAID-0) which differs from the first RAID level. Data is read from the two RAID arrays in parallel for improved read performance. A controller is responsive to a disk failure which results in data becoming inaccessible from one of the arrays to retrieve the data from the other one of the arrays. The redundancy within the first RAID array also enables the controller to restore data following a failure of one disk drive by reference to the remaining disk drives of the first array.

Methods, apparatus and controllers for a raid storage system

A method and apparatus for improving performance of a loop network, in particular a Fiber Channel Arbitrated Loop. The loop network has two loops and a plurality of dual-ported devices each with one port on each loop. The method includes selectively bypassing redundant ports on the loops by a first command means in the form of a Fiber Channel Arbitrated Loop command to balance port accesses and to reduce the loop overhead by reducing the number of ports in each loop. In the event of a fault, bypassing the port of a device by a second command means in the form of a non Fiber Channel Arbitrated Loop command and enabling all the bypassed redundant ports with a single command to all ports using the first command means. The first command means does not enable the port bypassed by the second command means.

Method and apparatus for improving performance of a loop network

Described is a method for processing work items in a data processing system. An interrupt is generated in response to receipt of a work item on a queue and the generated interrupt is serviced to schedule a task by placing the task on a task queue for later processing of the queued work item. The interrupt is not enabled at this point and therefore the receipt of further work items will not result in the generation of interrupts. When the scheduled task reaches the head of the queue, the task is executed to process the queued work item (and all other work items that have been added to the queue since the task was scheduled). When all the work items have been processed, a further task is speculatively scheduled for processing of any work items that are subsequently placed on the work item queue. When the speculatively scheduled task reaches the head of the queue, it is executed to process queued work items; if any work items were found, a further task is speculatively scheduled, otherwise the interrupt is enabled.

Data processing systems and method for processing work items in such systems

A method and apparatus for detection of a port name in a loop network is provided, particularly a loop network in the form of a Fibre Channel Arbitrated Loop (FC-AL). The loop network () has a plurality of devices () each device () having at least one port () on the loop network (). The method includes determining which ports () are populated with devices () for which the unique port name (WWPN) is not known. The populated ports are then all bypassed and a mode is entered on the loop network () in which idle frames are transmitted around the loop network (). One port is un-bypassed at a time and the port name from the un-bypassed port is received and recorded. The port name is received from the un-bypassed port in a Loop Initialisation Select Master (LISM) frame transmitted by the un-bypassed port.

Method and apparatus for detection of port name in a loop network

A method and apparatus for recovery from faults in a loop network () is provided. The loop network () has a host means (), a first loop and a second loop (), a plurality of ports () connected to each of the loops () and a control device () on or connected to each loop () with bypass control over at least one of the ports () connected to the loop (). In the event of a failure on the first loop (), the host means () instructs the bypassing of at least one port () on the first loop (), the host means () sending the instructions via the control device () on or connected to the second loop (). The host means () may determine the physical topology of the ports () on the first and second loops () such that when a failure is reported to the host means () by a port () on the first loop (), the host means () instructs the bypassing of a port () in a specific relationship to the reporting port () on the first loop (). The host means () may instruct the bypassing of all ports () on the first loop () and subsequently selectively un-bypass ports () to ascertain the location of a faulty port or ports.

A method and apparatus are provided for fault location in a loop network (). The network system having a host port () for supplying and receiving data and a plurality of successively connected ports () through which data from the host port () is transferred. A counter () for each port records data transfers in which the amount of data received at a destination port is less than an expected amount of data. When a transfer with less than the expected amount of data is identified for a data flow between a sending port () and a destination port (), the counters are incremented for each port () after the sending port up to and including the destination port. Analysing means determines a fault location in the network system from the distribution of counts in the counters ().

Method and apparatus for fault location in a loop network

A method is provided for remotely controlling power to electronic devices. Each device includes two or more ports for receiving signals over the serial link. The method includes issuing a shutdown command from the host data processing system to selected one of the devices over the link and responsive to the receipt of a power-off command at a device, causing the device to enter a low power standby mode on cessation of signal activity at one of the device ports. On entering standby mode at a device, standby power is supplied in the device to allow the device to monitor the one or more device ports for incoming signals. In addition, transmission of signals via the one or more ports is ceased. On receipt of a signal at any of the one or more ports that was previously inactive, power is restored to the device.

Remote power control

Text editing and subsequent reformatting of a document is performed in two separate stages run as two parallel processes with different priorities. The editing of text is performed as a high priority process directly on a selected portion of the document previously copied under control of edit/format control logic 7 from a document store 5 into a refresh buffer 3. The editing process takes each keystroke as it is received by control logic 7 from keyboard 8 and enters it into buffer 3. The contents of the buffer 3 are directly mapped onto a display screen 2 so that the updated portion of the document is immediately seen by the operator. Should insufficient space be available in buffer 3 to accommodate an edited line of text, space is made available by controlled wordspill of text from the line into auxiliary storage prior to execution of the editing operation. Reformatting of the edited text is conducted as a low priority process taking one line of the document at a time and any words in auxiliary store for inclusion in that line. Reformatting is interrupted by the occurrence of keystroke signals requiring further editing of the text.

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Christchurch, United Kingdom

Robert Frank Maddock