Crossroads Systems, Inc.

Hewlett-packard Company

Kip Cr P1 LP

Stephen G Dale

Bradfred W Culp

John F Tyndall

John B Haechten

An intermediate device communicatively connected to a host device and a sequential device in a storage area network. The host device is configured to issue different kinds of commands to the sequential device, including an inquiry command. The sequential device is configured to sequentially process requests from the host device. The intermediate device is configured to cache inquiry data about the sequential device itself in a cache memory connected to the intermediate device and service inquiry commands from the host device.

System and method for caching inquiry data about sequential access devices

A system and method for servicing an inquiry command from a host device requesting inquiry data about a sequential device on a storage area network. The inquiry data may be cached by a circuitry coupled to the host device and the sequential device. The circuitry may reside in a router. In some embodiments, depending upon whether the sequential device is available to process the inquiry command, the circuitry may forward the inquiry command to the sequential device or process the inquiry command itself, utilizing a cached version of the inquiry data. The cached version may include information indicating that the sequential device is not available. In some embodiments, regardless whether the sequential device is available, the circuitry may process the inquiry command and return the inquiry data from a cache memory.

System and method for inquiry caching in a storage area network

A system and method for servicing inquiry commands, wherein inquiry data is stored in a memory and if an inquiry command for a target device is received while the target device is busy processing another command, the stored inquiry data is returned in response to the command. In one embodiment, a router contains a memory for storing static inquiry data corresponding to each of a plurality of sequential devices connected thereto. The first time a host sends an inquiry command to one of the sequential devices, the router routes the command to the target device and stores the data returned by the device. Subsequent inquiry commands are serviced by passing the command through to the target device if it is not busy, or returning inquiry data from the router's memory if the target device is busy processing another command.

Inquiry data received from sequential target devices is stored in a cache memory. In one embodiment, the cache memory is coupled to a router. In one embodiment, when the router receives from a host an inquiry command about a target, the router first checks to see if the inquiry command can be serviced from the cache. If so, the inquiry data about the target is retrieved from the cache and returned to the host. If not, the router checks to see if the target is busy. If not busy, the router routes the inquiry command to the target and stores the inquiry data returned by the target in the cache. If the target is busy, the router places the inquiry command in a queue. When the target becomes available, the router forwards the inquiry command to the target for processing, thereby keeping the inquiry command from timing out.

System and method for servicing inquiry commands about target devices in storage area network

Embodiments of the present invention provide a system and method of command tracking that eliminates, or at least substantially reduces, the shortcomings of prior art systems and methods for command tracking. More particularly, embodiments of the present invention provide a system and method in which a command is assigned a unique identification. State information for the command (e.g., has the command been completed, has all the data associated with the command been received and other state information) can be associated with the unique identification and recorded. According to one embodiment, the state information can be stored in various tables that correspond to particular data transport protocols and/or devices. Because the state information for the command is associated with the unique identification in the tables, state information for the same command can be identified, even if the command changes data transport protocols.

System and method for command tracking

A system and method for servicing inquiry commands, wherein inquiry data is stored in a memory and if an inquiry command for the target device is received while the target device is busy processing another command, the stored inquiry data is returned in response to the command. In one embodiment, a router contains a memory for storing static inquiry data corresponding to each of a plurality of sequential devices connected thereto. The first time a host sends an inquiry command to one of the sequential devices, the router routes the command to the target device and stores the data returned by the device. Subsequent inquiry commands are serviced by passing the command through to the target device if it is not busy, or returning inquiry data from the router's memory if the target device is busy processing another command.

System and method for inquiry caching

Embodiments of a routing device for coordinating the interoperability of devices with varying capabilities that send and/or receive commands in a storage network are disclosed. A host device in the storage network may inquire the capabilities of a storage device in a storage network. A routing device may receive a response from the storage device and pass the response through to the host unaltered or may alter the response to reflect the higher or lower capabilities of the routing device before sending the response to the host.

Apparatus for coordinating interoperability between devices of varying capabilities in a network

Systems and methods for coordinating the interoperability of devices in a network are disclosed. Embodiments of the present invention may provide the ability for a host device in a storage network to inquire as to the capabilities of a storage device in a storage network. A routing device between the host and the storage device may receive a response, and if the routing device has a higher capability than the storage device the routing device may convert the response to a response that reflects the higher capabilities of the routing device before sending the response on to the host. However, if the storage device has a higher capability than the routing device, the routing device may pass the response through to the host unaltered.

Method and system for coordinating interoperability between devices of varying functionality in a network

Systems and methods for coordinating the interoperability of devices with varying capabilities are disclosed. A host device may inquire as to the capabilities of a storage device in a storage network. A routing device may receive this response, and if the routing device has a higher capability than the storage device the routing device may convert the response to a response that reflects the higher capabilities of the routing device before sending the response on to the host. However, if the storage device has a higher capability than the routing device, the routing device may pass the response through to the host unaltered so the host may take advantage of the capabilities of the storage device. Alternatively, the router may convert the response to a response that reflects the lower capabilities of the routing device before sending the response on to the host.

Growing community of inventors

Dripping Springs, TX, United States of America

Stephen G Dale