Micron Technology Incorporated

Xyratex Technology Limited

Marek Piekarski

Ian David Johnson

Finbar Naven

Paul Howarth

Simon William Farrow

Yves Constantin Tchapda

Brian Alan Whitehead

A method of managing a plurality of storage devices. The method comprises at a first device connected to the plurality of storage devices via a switch, receiving an indication of a plurality of logical disks, each logical disk being provided by a respective one of the plurality of storage devices. Each logical disk comprises a plurality of logical blocks. Data representing a virtual disk is generated, the virtual disk comprising a plurality of virtual blocks, each virtual block being provided by a logical block. Access is provided to the virtual disk to a second device different to the first device. A first virtual block is selected, the first virtual block being provided by a first logical block, and a re-mapping operation is performed after which the first virtual block is provided by a second logical block different to the first logical block.

Data storage management

A method for transmitting data packets from a first device through a switch to a second device is described. The method is performed at an intercepting device intermediate the first device and the switch device. The method comprises receiving a first data packet from the first device, determining that the first data packet is to be transmitted to the second device and determining whether the first data packet is of a first type that can not be transmitted from the intercepting device to the second device through the switch. If the first data packet is of the first type, the first data packet is encapsulated within a second data packet and transmitting the second data packet through the switch to the second device. If the first data packet is not of the first type, the method comprises transmitting the first data packet through the switch to the second device.

Encapsulation enabled PCIE virtualisation

A method of providing access to first data stored at a first device to a second device, the first device storing the first data in a memory accessible to said second device. The method comprises, at a control element distinct from each of said first and second devices accessing the stored first data in said memory accessible to said second device before said first data is accessed in said memory accessible to said second device by said second device.

Method and apparatus for providing data access

A failure of communication between a first device and a second device is managed. A failure of communication between the first device and the second device is detected at a third device intermediate. The first data is transmitted from the third device to the first device. The first data indicates that the second device is unusable by the first device.

Connection method

There is herein described a method for transmitting data packets from a first device through a switch to a second device. The method is performed at an intercepting device intermediate the first device and the switch device. The method comprises receiving a first data packet from the first device, determining that the first data packet is to be transmitted to the second device and determining whether the first data packet is of a first type that can not be transmitted from the intercepting device to the second device through the switch. If it is determined that the first data packet is of the first type, the method comprises encapsulating the first data packet within a second data packet, the second data packet being of a second type that can be transmitted from the intercepting device through the switch to the second device, and transmitting the second data packet through the switch to the second device. If it is determined that the first data packet is not of the first type, the method comprises transmitting the first data packet through the switch to the second device.

There is disclosed a data switch in combination with a proxy controller, the data switch being configured for routing data traffic and control traffic between at least one input/output (I/O) device and at least one server including a memory having an address space including set of data buffers and a list of command/status descriptors. The data switch is configured to: In this way, I/O devices can be virtualized, since only the control traffic (which generally comprises less than 10% of the bandwidth) needs be processed by the proxy controller.

Control path I/O virtualisation

A method for providing identifiers for virtual devices in a network. The method comprises receiving a discovery data packet directed to a physical network node associated with a physical endpoint device. A response to the discovery data packet directed to a physical network node is provided, the response comprising an identifier of a virtual device. At least one further discovery data packet directed at least to said virtual device is received. A response to a first one of the further discovery data packets is provided, the response comprising an identifier of a virtual endpoint device. At least some functionality of the virtual endpoint device is provided by the physical endpoint device.

Switching method

According to the present invention there is provided a scheduling and arbitration process for use in a digital data switching arrangement of the type in which a central switch under the direction of a master control provides the cross-connections between a number of high-bandwidth ports to which are connected on the ingress side of the central switch a number of ingress multiplexers, one for each high-bandwidth input port and on the egress side a number of egress multiplexers, one for each high-bandwidth output port, each ingress multiplexer including a set of N input queues serving N low-bandwidth data sources and a set of M virtual output queues serving M low-bandwidth output data sources, characterized in that the scheduling and arbitration arrangement includes three bandwidth allocation tables, an ingress port table associated with the input queues and having N&#xd7;M entries each arranged to define the bandwidth for a particular virtual output queue, an egress port table associated with the virtual output queues and having M entries each arranged to define the bandwidth allocation of a high-bandwidth port of the central switch to a virtual output queue and a central allocation table located in the master control and having (M&#xd7;N)entries each of which specifies the weights allocated to each possible connection through the central switch.

Distributed hierarchical scheduling and arbitration for bandwidth allocation

There is disclosed a masking unit (REQMSK) for use in a data packet switching system. The data switching system being of the type having a memoryless cross-back switch (SM) providing cyclic connections under the control of a switch arbiter (SCARB) between ingress routers (IR, IR, IRand IR) and egress routers (ER, ER, ERand ER). Each of the ingress routers (IR&#x2013;IR) is provided with incoming packet buffering on a virtual output queue basis (VOQ, VOQ, VOQ, and VOQfor ingress router IR). Each virtual output queue also produces a connection request signal REQto REQwhen the corresponding queue has a data packet in it. The masking unit REQMSK is arranged to randomly mask out correlated connection requests.

Data switching arbitration arrangements

A data switch is proposed of the type having virtual queue ingress routers interconnected with egress routers by way of a memoryless switching matrix controlled by a control unit which performs an arbitration process to schedule connections across the switch. This scheduling is performed to ensure that data cells which arrive at the ingress routers at unpredictable times are transmitted to the correct egress routers. Each ingress router further includes a queue for time division multiplex traffic, and at times when such traffic exists, the control unit overrides the arbitration process to allow the time division multiplex traffic to be transmitted through the switch.

Data switch and a method for controlling the data switch

In a data switching system, the ingress and egress ports of a memoryless cross-bar switch are controlled by an arbitration method. The arbitration method uses a three phase process involving (i) a request phase in which each ingress port sends its connection requests to egress ports to which a connection is required, (ii) a grant phase in which each egress port uses a grant pointer to select one of the requests directed to it using a grant pointer, and generates a grant signal, and (iii) an accept phase in which each ingress port selects one of the received grant signals to accept, so defining an ingress to egress port connection across the cross-bar switch. The transition sequences for each of the grant pointers are mutually exclusive, so that any synchronisation of the grant pointers is eliminated on the next arbitration cycle. This is arranged by a setting of the paths taken by request and grant signals.

Method and arbitration unit for digital switch

An arbitration process sets the connections to be made between ingress and egress ports of a crossbar switch of a data switching system. A weight parameter is used for each pair of ingress and egress ports. Connection requests are generated indicating ingress ports to be connected to egress ports. A selection is made among conflicting connection requests, to produce a connection proposal for each egress port. Any connection request for which respective weighting parameter is zero is not selected. When one of the connection requests is realised, the weight parameter corresponding to this connection is decreased by one. All the weight parameters for a given egress port are re-set to default values in the case that there are no connection requests for that egress port with non-zero weights.

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Macclesfield, United Kingdom

Marek Piekarski