Intel 8089

The Intel 8089 input/output coprocessor was available for use with the 8086/8088 central processor. It was announced on May 1979, but the price was not available at that time. It used the same programming technique as 8087 for input/output operations, such as transfer of data from memory to a peripheral device, and so reducing the load on the CPU. This I/O processor was available on July 1979 for US$194.20 in quantities of 100 or more.
Because IBM didn't use it in IBM PC design, it did not become well known; later I/O-coprocessors did not keep the x89 designation the way math coprocessors kept the x87 designation. It was used in the Apricot PC and the Intel Multibus iSBC-215 Hard disk drive controller. It was also used in the Altos 586 multi-user computer. Intel themselves used the 8089 in their reference designs (which they also commercialized) as System 86.