VMware handles I/O somewhat differently from the manner in which IBM handles it. In the case of VMware, instead of a separate partition and dedicated I/O system, the hypervisor handles I/O itself. "We provide a virtual device or virtualized drivers for Intel E1000 and AMD VLANCE," said VMware's Chief Platform Architect Richard Brunner. He said that the company also provides a virtual device called VMXnet. "When these devices attempt to access physical hardware, all their writes are trapped to the hypervisor, which turns around and places the request in a stack in the hypervisor," said Brunner. He added that the hypervisor has a queue that the physical device driver then has to take care of.
Read the full interview by Wayne Rash at Server Watch