Patent ID: 6216209
Filing Date: 2001-04-10
Classification: G06F

Abstract:
An article of manufacture, comprising:at least one computer usable medium having computer readable program code moans embodied therein for 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, the computer readable program code means in the article of manufacture comprising:(i) computer readable program code means for causing a computer to write blocks of data from a client process of the client node to a first storage tape of a first server node, 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;(ii) computer readable program code means for causing a computer to switch writing blocks of data from said client node to a second storage tape of a second server node if the physical end of storage is reached for the first storage tape, wherein the switching writing is transparent to the client process;(iii) wherein the writing of blocks of data from the client process of the client node to the first storage medium and to the second storage medium comprises a write-behind operation, with said first server node and said second server node periodically notifying the client node whether previously received blocks of data have been correctly written to the first storage tape or the second storage tape, respectively;(iv) wherein said computer readable program code means for causing a computer to switch writing blocks of data to said second storage tape of said second server node occurs without loss of block of data to be stored by said client process of the client node, and wherein said method further comprises computer readable program code means for causing a computer to detect said physical end of storage of said first storage tape when writing blocks of data thereto, and computer readable program code means for causing a computer to buffer 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 computer readable program code means for causing a computer to return 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.