Data operand fetching control includes calculating a summation weight value for each instruction in a pipeline, the summation weight value calculated as a function of branch uncertainty and a pendency in which the instruction resides in the pipeline relative to other instructions in the pipeline. One system includes a processor-addressable physical memory and a processor in communication with the processor-addressable physical memory and configured to execute an environment and to allocate an environment memory to the environment. The machine may include a plurality of hardware devices which are accessible through the fascia. The ribs are designed to be relatively flexible under lateral loads.