Abstract: A peripheral device subsystem enables its peripheral devices to operate asynchronously with respect to attaches hosts through the use of managed buffers, new multiple data transfer modes, control and error recovery operations. In a preferred first or buffer mode of operation, all data of each record being transferred can be resident in a buffer before transfer to either a host or device. For a host to device write transfer, receipt of such a record by the buffer results in the subsystem signaling to the host a completion of a transfer to an addressed device even though the device has received none or only part of the data. In a second or tape write mode, recording data in a peripheral device, such as a tape recorder, completion of recording is not signaled until after the buffer has transferred the data to the recorder.

Abstract: A peripheral device subsystem enables its peripheral devices to operate asynchronously with respect to attaches hosts through the use of managed buffers, new multiple data transfer modes, control and error recovery operations. In a preferred first or buffer mode of operation, all data of each record being transferred can be resident in a buffer before transfer to either a host or device. For a host to device write transfer, receipt of such a record by the buffer results in the subsystem signaling to the host a completion of a transfer to an addressed device even though the device has received none or only part of the data. In a second or tape write mode, recording data in a peripheral device, such as a tape recorder, completion of recording is not signaled until after the buffer has transferred the data to the recorder.

Abstract: A peripheral subsystem, such as a tape storage subsystem, assigns logical and physical values to blocks of signals received from a host. A host can retrieve such values for use later to locate the blocks of signals and for error recovery purposes. In a buffered peripheral subsystem, such values define current signal transfer status of the buffer.