1. A method for performing an input/output process containing a programmed input/output instruction in a multiprocessor system including at least two processors, each of said processors being coupled to an I/O bus with one or more I/O devices connected thereto, said multiprocessor system including an operating system having process scheduling means for executing processes on said processors according to assigned priority, said process scheduling means including a process control block containing scheduling information for each of said processes said method comprising the steps of: establishing a global device location table accessible by each of said processors in which a unique I/O device address and a corresponding I/O bus location are stored for each I/O device in said multiprocessor system; when starting a programmed input/output instruction, determining the unique address of a referenced I/O device; reading the corresponding I/O bus location of the referenced I/O device from the global device location table; determining whether the referenced I/O device is connected to the local I/O bus, and when the referenced I/O device is connected to the local I/O bus, executing the input/output process on the local processor, when the referenced I/O device is connected to a prescribed remote I/O bus, placing a locked descriptor in the process control block for the input/output process indicating that the input/output process can be performed only on the remote processor coupled with the prescribed remote I/O bus, saving the registers of the input/output process in its process control block, scheduling the input/output process on the remote processor coupled with the prescribed remote I/O bus in accordance with the priority assigned to the I/O process by the operating system, and executing the input/output process on the remote processor coupled with the prescribed remote I/O bus.