Up Your ACP

Ancillary control processors are part of the RSX-11M I/O mechanism. They implement device protocols for a variety of I/O devices. Because the operation of ACP's is hidden from the programmer, they have been considered untouchable in the past. Conceptually, however, an ACP is nothing more than a task which is tied to a device driver via the I/O mechanism. As this manual will show, the interface between an ACP and a driver is very simple and allows ACP's to be a powerful tool for system developers.