A PRAM includes a memory cell array of phase change memory cells, and a write circuit receiving an externally provided first voltage and supplying a write pulse for writing data to the memory cells in a normal operation mode. The horizontal situation indicator receives the display signals from the processor and displaying symbology representing the heading-based leg. In a third aspect, the present disclosure encompasses polycarbonate polyol compositions characterized in that the polymer chains have a high percentage of \u2014OH end groups and a high percentage of carbonate linkages.