Abstract: A direct memory access (DMA) circuit which is physically positioned with an input/output device, the DMA circuit storing a first reference value pointing to a data structure which describes a buffer portion of system memory in which data is stored for transfer to the I/O device, a value determining a position within the buffer portion of system memory beginning at which a next sequence of data is to be placed, and a value determining a position within the buffer portion of system memory from which a next sequences of data is to be copied to the I/O device, the DMA circuit including circuitry for reading data from the buffer portion of system memory beginning at the position from which a next sequences of data is to be copied and for writing the data read to the I/O device.

Abstract: A direct memory access (DMA) circuit which is physically positioned with an input/output device, the DMA circuit storing a first reference value pointing to a data structure which describes a buffer portion of system memory in which data is stored for transfer to the I/O device, a value determining a position within the buffer portion of system memory beginning at which a next sequence of data is to be placed, and a value determining a position within the buffer portion of system memory from which a next sequences of data is to be copied to the I/O device, the DMA circuit including circuitry for reading data from the buffer portion of system memory beginning at the position from which a next sequences of data is to be copied and for writing the data read to the I/O device.

Abstract: A direct memory access (DMA) circuit which is physically positioned with an input/output device, the DMA circuit storing a first reference value pointing to a data structure which describes a buffer portion of system memory in which data is stored for transfer to the I/O device, a value determining a position within the buffer portion of system memory beginning at which a next sequence of data is to be placed, and a value determining a position within the buffer portion of system memory from which a next sequences of data is to be copied to the I/O device, the DMA circuit including circuitry for reading data from the buffer portion of system memory beginning at the position from which a next sequences of data is to be copied and for writing the data read to the I/O device.

Abstract: A direct memory access (DMA) circuit which is physically positioned with an input/output device, the DMA circuit storing a first reference value pointing to a data structure which describes a buffer portion of system memory in which data is stored for transfer to the I/O device, a value determining a position within the buffer portion of system memory beginning at which a next sequence of data is to be placed, and a value determining a position within the buffer portion of system memory from which a next sequences of data is to be copied to the I/O device, the DMA circuit including circuitry for reading data from the buffer portion of system memory beginning at the position from which a next sequences of data is to be copied and for writing the data read to the I/O device.

Abstract: A direct memory access (DMA) arrangement having a DMA circuit which is positioned with an input/output device, the DMA circuit including a first register for storing a reference value pointing to a first data structure established by an application program which includes details of a transfer buffer in memory in which data is stored for transfer to the I/O device, two additional registers for storing an address and a range at which the data is stored within the transfer buffer in memory, and a fourth register for storing a reference value pointing to a second data structure which includes details describing a notification area of memory at which a notification from the DMA circuit that a transfer of data has been completed may be stored.