The Mass Storage Control Protocol (MSCP) is a protocol that was designed by Digital Equipment Corporation of Maynard, Massachusetts for the purposes of controlling their high-end mass storage options.
Designed to minimize the amount of CPU involvement, the protocol depends upon two queues.
Into one queue are placed packets which fully describe the commands to be executed by the mass storage subsystem.
I/O-space reads and writes to the MSCP controller, a less-expensive but still-costly operation, are similarly minimized.
The dependence upon in-memory packets and the minimization of interrupts and I/O-space reads and writes greatly facilitates remote operations.