Patent ID: 6223262
Filing Date: 2001-04-24
Classification: G06F

Abstract:
A method of storing data in a distributed processing system having multiple processors, one processor being a client node and one or more other processors each being a server node, each server node having at least one storage tape associated therewith, said method comprising:writing blocks of data from a client process of the client node to a first storage tape of a first server node of the distributed processing system, said writing continuing until all blocks of data to be stored by said client process are written to said first storage tape or a physical end of storage is reached for the first storage tape, wherein said physical end of storage is reached without size of said first storage tape having been predetermined;if said physical end of storage is reached for said first storage tape, switching writing blocks of data from said client node to a second storage tape of a second server node of the distributed processing system, wherein said switching writing is transparent to said client process of said client node;wherein said writing blocks of data from said client process of the client node to said first storage tape and to said second storage tape each comprises a write-behind operation, and wherein said first server node and second server node periodically notify the client node whether previously received blocks of data have been correctly written to the first storage tape or the second storage tape, respectively;wherein said switching writing blocks of data to said second storage tape of said second server node occurs without loss of blocks of data to be stored by the client process of the client node and wherein said method further comprises detecting said physical end of storage of said first storage tape when writing blocks of data thereto, and buffering at the first server node unwritten blocks of data received subsequent to said detecting said physical end of storage for return to said client node; andfurther comprising returning said unwritten blocks of data from the first server node to the client node after notifying the client node that said physical end of storage of said first storage tape has been reached.