Abstract: Methods and apparatus for data distribution among servers in a grouped server system. Each server in the group includes a device manager which is responsible for brokering devices to services. A service communicates to a device manager on the same server through an inter-process communication mechanism. A desktop unit, having persistent connections with a single device manager, switches to a peer (other device managers in the group) when the desktop unit is reset or when a device manager fails. At least one device is connected to the desktop unit. When the desktop unit is connected to the new device manager, ownership of the devices may change. The new device manager notifies its peers of any device status changes.

Abstract: A method and apparatus is provided for integrating a logic level simulation with an instruction level simulation for more accurate and faster system level simulation for testing. A host system or processors (CPU) is simulated by the instruction level simulator and the simulation of an input/output subsystem is modeled by the logic level simulator. The two simulations work side by side communicating through an interprocess communication (IPC) device and both simulations can perform a read/write access. Hence, a DMA and a slave access can occur at the same time causing a deadlock situation where both simulators are waiting for data and acknowledgment from each other at the same time. An input/output subsystem SBus module resolves this deadlock by deferring the non-DMA transaction. Finally, the synchronization of the two simulations is handled by the invention allowing the two simulators to run as asynchronous peers.