A system where boxes move along a conveyor belt and a bar code scanner reads bar codes on the boxes and detects the presence of a box, which facilitates establishing a box detector that detects the leading edge of a box. A scheduler is employed to balance a CPU-intensive workload imposed by virtual machines, each having a plurality of virtual processors supported by a root partition, across various logical processors that are running threads and inputoutput operations in parallel. Responsive to receipt of a presentation requirement specifying an overlay stored in a memory device, the rasterizing processor determines whether an overlay instance for the overlay is cached in a memory system.