Every peripheral device has a unique identity. A stub on the local machine understands the NOS I/O port protocol and translates the protocol to the series of local operating system calls to manage the local peripheral. The results are then returned back through the port.
Example peripheral devices might include printers, CDROMs, disks, tapes, CD Recorders, and floppy disk.
Peripheral actions might include load or unload device driver, and allocated or unallocated device. Some device specific actions might include read, write, and seek.