Synchronous input / output hardware acknowledgement of write completions

A system for communicating completion of synchronous input/output (I/O) commands comprising:

• a server comprising processor executing an operating system;
• and
• a recipient control unit comprising a processor operatively connected to the server;
• wherein the server is configured to:
• issue, by a processor, a Synchronous I/O command to the recipient control unit;
• receive a direct memory access (DMA) read response from the recipient control unit;
• convert the DMA read response to a DMA write in a memory of the recipient control unit;
• issue the DMA read request to the recipient control unit, wherein the DMA read request comprises an echo read portion comprising at least one byte of information at the end of a record;
• receive, by the processor, a DMA write confirmation comprising the echo read portion of the record;
• and
• write the echo read portion to a status area.

A computer program product for communicating completion of synchronous input/output (I/O) commands between a processor executing an operating system and a recipient, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause the processor to perform a method comprising:

• issuing, by the processor, a Synchronous I/O command to the recipient control unit;
• receiving, with the processor, a direct memory access (DMA) read response from the recipient control unit;
• converting, with the processor, the DMA read response to a DMA write response in a memory of the recipient control unit;
• issuing the DMA read request to the recipient control unit, wherein the DMA read request comprises an echo read portion comprising at least one byte of information at the end of a record;
• receiving, by the processor, a DMA write confirmation comprising the echo read portion of the record;
• and
• writing the echo read portion to a status area.