Patent ID: 7069365

Claim:
A computer system, comprising a storage device comprising a plurality of bit positions and operably coupled to a plurality of electrical terminals, wherein a first portion of the electrical terminals is adapted for coupling to a first device, and wherein a second portion of the electrical terminals is adapted for coupling to a second device; a first device driver configured to control the first device by accessing the storage device and writing a value to a first portion of the bit positions; a second device driver configured to control the second device by accessing the storage device and writing a value to a second portion of the bit positions; and a nexus device driver operably coupled between the first and second device drivers and the storage device, and configured to grant exclusive access to the storage device to either the first or the second device driver; wherein said granting exclusive access comprises: detecting that a given device driver is attempting to modify one or more of the bit positions; determining which of the bit positions the given device driver owns; preventing the given device driver from modifying any of the bit positions of the storage device if one or more of the bit positions that the given device driver is attempting to modify is not owned by the given device driver; granting the given device driver access to the storage device if all of the bit positions the given device driver is attempting to modify are owned by the given device driver; preventing the second device driver from writing a value to the second portion of the bit positions if the first device driver is granted access to the storage device; and preventing the first device driver from writing a value to the first portion of the bit positions if the second device driver is granted access to the storage device.