Abstract: A computer configured for managing multiple processing threads is susceptible to deadlocks or hangs when resources needed by one process are locked by another process that is not progressing. Locking relationships are created and released so quickly that rigidly monitoring these relationships would consume more computer power than are being monitored. An approach to determining the existence of a deadlock or hang uses a first ‘snapshot’ showing an approximation of locking relationships and then verifies a deadlock or hang using a second snapshot to determine if a suspected deadlock or hang is still present.

Abstract: An application programming interface (API) that leverages operating system instrumentation to provide a chain of threads and processes may alleviate some debugging complications. Specifically, the chain may start with the first thread in the process that experienced the original failure and end with the last thread upon which the first thread directly or indirectly depends. The API may aid debugging efforts by classifying all threads related or dependent upon an original failed thread into specific categories of failures, requesting further information from the originating OS concerning specific failed threads, and using that information to debug the failed application or process more thoroughly.

Abstract: A virtual file system and method. The system architecture enables a plurality of underlying file systems running on various file servers to be “virtualized” into one or more “virtual volumes” that appear as a local file system to clients that access the virtual volumes. The system also enables the storage spaces of the underlying file systems to be aggregated into a single virtual storage space, which can be dynamically scaled by adding or removing file servers without taking any of the file systems offline and in a manner transparent to the clients. This functionality is enabled through a software “virtualization” filter on the client that intercepts file system requests and a virtual file system driver on each file server. The system also provides for load balancing file accesses by distributing files across the various file servers in the system, through migration of data files between servers.

Abstract: A virtual file system and method. The system architecture enables a plurality of underlying file systems running on various file servers to be “virtualized” into one or more “virtual volumes” that appear as a local file system to clients that access the virtual volumes. The system also enables the storage spaces of the underlying file systems to be aggregated into a single virtual storage space, which can be dynamically scaled by adding or removing file servers without taking any of the file systems offline and in a manner transparent to the clients. This functionality is enabled through a software “virtualization” filter on the client that intercepts file system requests and a virtual file system driver on each file server. The system also provides for load balancing file accesses by distributing files across the various file servers in the system, through migration of data files between servers.

Abstract: A virtual file system and method. The system architecture enables a plurality of underlying file systems running on various file servers to be “virtualized” into one or more “virtual volumes” that appear as a local file system to clients that access the virtual volumes. The system also enables the storage spaces of the underlying file systems to be aggregated into a single virtual storage space, which can be dynamically scaled by adding or removing file servers without taking any of the file systems offline and in a manner transparent to the clients. This functionality is enabled through a software “virtualization” filter on the client that intercepts file system requests and a virtual file system driver on each file server. The system also provides for load balancing file accesses by distributing files across the various file servers in the system, through migration of data files between servers.