Abstract: A method for controlling an underlying physical network by a software defined network includes providing a physical network that comprises routers for routing data traffic on a data communication plane, providing a software defined network that comprises at least one controller and at least one feature on a control plane for controlling the data forwarding elements of the physical network, communicating, by the data forwarding elements of the data communication plane, with the controller of the control plane on a dedicated control channel, communicating, by the controller, with the at least one feature on a dedicated feature channel in the control plane, and exchanging, via the data communication plane, at least a portion of the data traffic in the control plane.

Abstract: A method for controlling an underlying physical network by a software defined network includes providing a physical network that comprises routers for routing data traffic on a data communication plane, providing a software defined network that comprises at least one controller and at least one feature on a control plane for controlling the data forwarding elements of the physical network, communicating, by the data forwarding elements of the data communication plane, with the controller of the control plane on a dedicated control channel, communicating, by the controller, with the at least one feature on a dedicated feature channel in the control plane, and exchanging, via the data communication plane, at least a portion of the data traffic in the control plane.

Abstract: A computer system having a shared disk file system running on multiple computers each having their own instance of an operating system and being coupled for parallel data sharing access to files residing on network attached shared disks. Methods are provided for use as a parallel file system in a shared disk environment by use of a scaleable directory service for the system with a stable cursor, and a segmented allocation map. Dynamic prefetch and cached balance pools for multiple accesses improve the system. Extended file attributes are used for implementation of Access Control Lists in a parallel file system. A metadata node manages file metadata for parallel read and write actions. For our system, tokens are used for metadata node selection and identification. We have provided recoverable local shares for quota Management.

Abstract: A computer system having a shared disk file system running on on multiple computers each having their own instance of an operating system and being coupled for parallel data sharing access to files residing on network attached shared disks. Methods are provided for use as a parallel file system in a shared disk environment by use of a scalable directory service for the system with a stable cursor, a segmented allocation map. Synchronous and asynchronous takeover of a metadata node occurs for correction of metadata which was under modification and a new computer node to be a metadata node for that file. Locks are not constantly required to allocate new blocks on behalf of a user. We have provided recoverable local shares for Quota Management. A quota server and a quota client are provided for each file system, and a quotacheck utility allows parallel environments with minimal interference to other applications which require the use of quotas.