The Intel 8089 input/output coprocessor was available for use with the 8086/8088 central processor. 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.
Because IBM didn't use it in IBM PC design, it did not become well known; later IO coprocessors did not keep the x89 designation the way math coprocessors kept the x87 designation.