Patent ID: 6098117
Filing Date: 2000-08-01
Classification: G06F

Abstract:
A method for controlling read/write access to a register space of an I/O module in a distributed I/O system, the distributed I/O system including a computer system coupled to a module bank, the module bank including a communication module and one or more I/O modules, wherein the I/O module includes a register space, wherein the I/O module is coupled to the communication module, the method comprising:a first process executing in the communication module requesting access to the register space of the I/O module, wherein said requesting access includes initiating a first read operation on a semaphore register;the I/O module determining if a process executing in the communication module already controls access to the register space of the I/O module;the I/O module granting register space access to the first process executing in communication module;wherein the granting includes providing information to the first process indicating whether a process executing in the communication module already controls access to the register space of the I/O module;wherein the information is useable by the first process to affect register accesses by the first process.