Memory array architectures and operating methods suitable for super high density in the giga bits for multilevel nonvolatile memory integrated circuit system. The array architectures and operating methods include: (1) an Inhibit and Select Segmentation Scheme; (2) a Multilevel Memory Decoding Scheme that includes a Power Supply Decoded Decoding Scheme, a Feedthrough-to-Memory Decoding Scheme, a Feedthrough-to-Driver Decoding Scheme, and a Winner-Take-All Kelvin Memory Decoding Scheme; (3) a constant-total-current-program scheme; (4) includes fast-slow and 2-step ramp rate control programming; and a reference system method and apparatus, which includes a Positional Linear Reference System, a Positional Geometric Reference System, and a Geometric Compensation Reference System. The apparatus and method enable multilevel programming, reading, and margining.