Abstract: A method and apparatus for preserving call-state information on a wireless communication system is provided. The method includes periodically replicating stable call call-state information between a first and second processor via a network connection. The method also includes performing a transient clear to drop transient calls in existence at the time of an outage of an active first RCS application process or processor. The method also includes forming network-based active call facilities paths to a second RCS application instance and transitioning the second RCS application instance to an active state thereby avoiding a service interruption for the stable calls previously handled by the active first RCS application instance.

Abstract: A method and apparatus for preserving call-state information on a wireless communication system is provided. The method includes periodically replicating stable call call-state information between a first and second processor via a network connection. The method also includes performing a transient clear to drop transient calls in existence at the time of an outage of an active first RCS application process or processor. The method also includes forming network-based active call facilities paths to a second RCS application instance and transitioning the second RCS application instance to an active state thereby avoiding a service interruption for the stable calls previously handled by the active first RCS application instance.

Abstract: A method and an apparatus for providing scalable layers of highly available applications using loosely coupled commercially available computers. The software running on the loosely coupled computers is divided into three layers: the system layer, the platform layer, and the application layer, each having its own process group activation and fault recovery strategy. A process group contains software processes that depend upon a set of resources common to the process group. In addition to depending upon a common set of resources, processes within a process group share a fault recovery strategy. Fault recovery is performed at the process group level, such that if one process within a process group fails, fault recovery is takes place for all processes within the process group. In the preferred embodiment, an application layer process group may be paired with another application layer process group on a separate computer.

Abstract: A computer system having a scaleable software architecture is disclosed. The scaleable communication or data replication architecture that enables transparent replication of data or state information over a network of geographically dispersed processing units. Transparent data replication over a geographically dispersed computer network is useful in applications such as parallel computing and disaster recovery. The communication architecture also provides a transparent interface to a kernel I/O subsystem, device drivers and system applications. The communication architecture provides a distributed data model presenting a single system image of the I/O subsystem that allows two or more geographically dispersed processing units or clusters thereof, access to common data. In one particular implementation, the communication architecture permits RAID algorithms, such as RAID level 1 and RAID level 5 state information to be applied to the geographically dispersed network for site disaster recovery.

Abstract: A method whereby a host computer system is informed of the drive status in a disk array when one or more of the disk drives fail. A data pattern (timestamp or status code) is written on each of the disk drives in service in the array when an event occurs which changes the operating state of an array. The state of an array changes only when the array is configured, unconfigured, a disk drive fails, parity is marked inconsistent or the array is restored. The timestamp includes a binary number to allow the system to determine the status of each disk drive in the array. At each state, the timestamp on each of the operating disk drives is updated to reflect the number of operating disk drives and the status of the parity data. The distinct binary numbers that result when the array changes states allow the system to maintain the data integrity of the array.

Abstract: A scalable software architecture, for optimal performance on a RAID level 1, 3, 4 and 5 disk array or tape array. The software architecture consists of a software device driver and one or more driver daemon processes to control I/O requests to the arrays. Implemented in a UNIX or NetWare operating environment, this architecture provides a transparent interface to the kernels I/O subsystem, physical device drivers and system applications. The array driver and I/O daemon can be run on a uni-processor or multi-processor system platform to optimize job control, error recovery, data recreation, parity generation and asynchronous writes.

Abstract: An architecture for on-line reconfiguration on a RAID level 0, 1, 2, 3, 4 or 5 disk array. This architecture allows the computer system to perform reconfiguration of the disk array transparently, with disk I/O operations being performed concurrently with reconfiguration operations. The reconfiguration process allocates computer system resources necessary to support both the old and new array configurations during the reconfiguration process. Logical areas within the array are sequentially reconfigured from the old configuration to the new configuration. Data in each logical area is read from the area undergoing reconfiguration and thereafter overwritten in accordance with the new array configuration. System I/O requests received during reconfiguration which are directed to unreconfigured areas in the disk array are executed in accordance with the old array configuration.