A method, apparatus, system, and signal-bearing medium that, in an embodiment, calculate scores for cells within a program based on a speed at which the cells were presented and a frequency that the cells were presented. The trap handler architecture minimizes design complexity and verification efforts for concurrently executing threads by imposing a property that all thread groups associated with a streaming multi-processor are either all executing within their respective code segments or are all executing within the trap handler code segment. The system according to certain embodiments reads a previously stored signature value corresponding to a respective data block for sending from a backup storage system having at least one memory device to a secondary storage system.