bytezaehlergebnisbehandlung in a serial kanalerweiterung with buffering of vorausgeholten data.

摘要

A channel subsystem is provided with a conventional serial extender link that causes communications between a channel (12) and a control unit (18) to be delayed by the additional time to transmit a message in one direction and to transmit an acknowledgement in the other direction, and it has a buffer and associated components (called a channel outboard box 22) that are used for prefetching data from processor memory or from a peripheral device without waiting for the acknowledgement routines that are commonly used on both an interlocked data transfer and a non-interlocked transfer (called data streaming). A system of counters and other components and associated operations is provided that maintains the correct byte count that would otherwise be maintained in a system without the prefetch buffer and with only a short serial link. A system of count and status frames is provided for sending byte count and other status information between the channel and the outboard box.