Abstract: An agent loaded in a computer's operating system (OS) simulates disconnection and reconnection of a device, with no need to actually disconnect the device logically from a computer. During simulated reconnection, when the OS requests the hardware ID of the device, the agent returns a substitute ID, which causes the OS to load a substitute driver. Substitution of the ID also allows driver substitution for a not yet logically connected device; in this cases, no simulated disconnection or reconnection is needed. Driver substitution is dynamic and reversible, with no need to restart the system or reboot the OS and substitution of a driver for one device of a type does not disturb other devices of the same type. The invention may be implemented entirely in software, with no need for hardware modifications or device customization.

Abstract: Guests, such as virtual machines, that are running on a host hardware platform are selectively descheduled when an idling condition is detected. An example of the idling condition is that the guest has been executing instructions in an idle loop for more than a threshold period. Guest instructions may be evaluated for the idling condition in conjunction with binary translation.