1. A virtual machine operating system comprising: a first work queue in a memory; a second work queue in a memory; a first virtual machine including a first program function to assign a first work item to said first work queue and a second work item to said second work queue, and including a second program function to schedule work items from said first work queue for execution by said first virtual machine, said first and second work items originating from said first virtual machine, said first and second work queues being directly accessible by said first program function, said first work queue being directly accessible by said second program function; and a second virtual machine including a third program function to assign a third work item to said first work queue and a fourth work item to said second work queue, and including a fourth program function to schedule work items from said second work queue for execution by said second virtual machine, said third and fourth work items originating from said second virtual machine, said first and second work queues being directly accessible by said third program functions, said second work queue being directly accessible by said fourth program function; and wherein said memory is shared by said first and second virtual machines.