Abstract: An apparatus and method for improving the input/output performance of a computer system under the control of a multi-tasking, multi-threaded operating system. In particular, the invention provides an apparatus and method to chain contiguous DMA scatter gather sub blocks of a PRD table for channel 0 with contiguous DMA scatter gather sub blocks of a PRD table for channel 1, using a single data manager, while maintaining maximum media bandwidth. DMA block transfers are scheduled based on the availability of data from the I/O device's buffer memory, thus minimizing both media or network idle time as well as minimizing I/O bus idle time. Near maximum aggregate bandwidth of multiple I/O buses and their associated devices is obtained. The apparatus and method thus provides significant performance advantages over prior techniques having two I/O channel systems implemented with a single data manager.

Abstract: A method an corresponding apparatus for improving the input/output performance of a computer system under the control of a multi-tasking, multi-threaded operating system. In particular, the invention provides an apparatus and method to interleave contiguous DMA scatter/gather sub blocks of a PRD table corresponding to a first I/O channel with contiguous DMA scatter/gather sub blocks of a PRD table corresponding to a second I/O channel, using a single data manager, while maintaining maximum media bandwidth. DMA block transfers are scheduled by the single data manager based on the availability of data from the I/O devices' buffer memories, thus minimizing both media or network idle time as well as minimizing I/O bus idle time. Near maximum aggregate bandwidth of multiple I/O buses and their associated devices is obtained. The apparatus and method thus provides significant performance advantages over prior techniques having two I/O channel systems implemented with a single data manager.